Term
What is the difference between primary and secondary endocrine glands? |
|
Definition
primary glands secrete hormones as their primary function whereas secondary glands secrete hormones as the secondary function |
|
|
Term
List some primary endocrine glands |
|
Definition
Hypothalamus Pit gland Pineal gland Thyroid Adrenal Parathyroid Pancreas Gonads Placenta |
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|
Term
List some secondary endocrine glands |
|
Definition
Heart Kidneys Liver Stomach Si Skin |
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|
Term
Describe the endocrine action of hormones |
|
Definition
1. Specialised cells in endocrine gland secrete hormones into circulation 2. Hormones are transported through the body 3. Target cells respond only to the hormone for which they have a receptor |
|
|
Term
What does the concentration of a hormone in plasma depend on? |
|
Definition
1. rate and pattern of secretion 2. rate of removal (eg metabolism or excretion) 3. degree of binding (eg plasma to protein) (ie free vs bound) |
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|
Term
What is hormone concentration useful for? |
|
Definition
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|
Term
The release of most hormones in the body follow _____ patterns and is regulated by ________ |
|
Definition
pulsatile stimulating/inhibitory feedback loops |
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|
Term
Describe a circadian rhythm and name 2 hormones that follow it |
|
Definition
changes that follow a 24 hour cycle cortisol and growth hormone |
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|
Term
Describe a ultradian rhythm and name 2 hormones that follow it |
|
Definition
multiple release peaks in a day Luteinizing hormone (LH) and Follicle stimulating hormone (FSH) |
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|
Term
What is a episodic pattern? |
|
Definition
release in response to a particular stimulus |
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|
Term
What are the 3 classes of hormones? |
|
Definition
1. Derived from amino acids (eg tyrosine) 2. Protein based hormones 3. derived from lipids |
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|
Term
Name some hormones derived from amino acids |
|
Definition
Adrenaline and noradrenaline |
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|
Term
Name some protein based hormones |
|
Definition
peptides and glycoproteins |
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|
Term
What does cholesterol produce? |
|
Definition
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|
Term
What does arachidonic acid produce? |
|
Definition
eicosaniods (eg prostoglandins) |
|
|
Term
What is the function of the thyroid? |
|
Definition
to take iodine, found in many foods, and convert it into thyroid hormones: thyroxine (T4) and triiodothyronine (T3) |
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|
Term
How is T4 transported around the body? |
|
Definition
T4 is lipophilic so it binds to plasma proteins long half life (days) |
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|
Term
What hormones are derivatives of tyrosine? |
|
Definition
- thyroid hormones secreted by thyroid gland (eg T4) - catecholamines (eg adrenaline/noradrenaline and dopamine) |
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|
Term
Where is adrenaline/noradrenaline secreted from? |
|
Definition
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|
Term
Where is dopamine secreted fro? |
|
Definition
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|
Term
How are catecholamines transported around the body? |
|
Definition
they are water soluble and transported in the blood short half life (5-10mins) |
|
|
Term
Give a derivative of derivative of tryptophan |
|
Definition
melatonin which is secreted by the pineal gland |
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|
Term
Name some peptide derivatives |
|
Definition
Glycoproteins: TSH, LH, FSH, EPO, inhibin Short polypeptides and small proteins |
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|
Term
Where is TSH, LH and FSH released from? |
|
Definition
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|
Term
Where is EPO released from? |
|
Definition
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|
Term
Where is inhibin released from? |
|
Definition
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|
Term
Describe how a peptide/protein hormone is synthesised, stored and secreted? |
|
Definition
1. activation of a gene followed by transcription and translocation of the protein and modification (in Golgi apparatus) 2. fully mature proteins are then 'packaged' into membrane bound vesicles 3. vesicles pinch off into either secretory or storage vesicles 4. they are released from the cell via exocytosis (Ca2+ dependent) |
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|
Term
Why are hormones stored this way? |
|
Definition
to allow for rapid response to a stimulus |
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Term
Describe the events that follow an IV infusion of glucose |
|
Definition
1. blood glucose levels rise much faster than oral admin 2. rapid ACUTE phasic release of pre-synthesised stored insulin from pancreatic beta cells 3. this is supplemented over time with the release of newly synthesised hormone in CHRONIC phase |
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|
Term
How long does the chronic phase last? |
|
Definition
as long as the glucose challenge |
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|
Term
What happens to the inactive form of a hormone? |
|
Definition
1. preprohormone is enzymatically cleaved at the Golgi apparatus 2. prohormone is enzymatically cleave din the storage vesicle |
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|
Term
What happens to the active form of a hormone? |
|
Definition
active hormone is secreted cellularly and is followed by enzymatic cleavage into hormone derivatives |
|
|
Term
What lipid derivative hormones are there? |
|
Definition
1. eicosanoids (fatty acids derived from arachidonic acid) 2. steroid hormones (structurally similar to cholesterol) eg estradiol |
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|
Term
What eicosanoids are there? |
|
Definition
leukotrienes prostaglandins thromboxanes prostacyclins |
|
|
Term
Where are steroid hormones secreted from? |
|
Definition
adrenal cortex gonads placenta |
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|
Term
What are examples of steroid hormones? |
|
Definition
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|
Term
steroid hormones are ___ soluble |
|
Definition
steroid hormones are lipid soluble and can therefore cross membranes easily |
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|
Term
How are steroid hormones stored? |
|
Definition
They are not. They are secreted as they are produced "constitutive secretion" and are therefore not stored in vesicles |
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|
Term
Following a stimulus, how long does it take for steroid hormones detectable in plasma? |
|
Definition
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|
Term
Following a stimulus, how long does it take for steroid hormones to achieve maximum secretion rates? |
|
Definition
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|
Term
Describe steroidal affinity |
|
Definition
Very high and are therefore very effective at low concentrations |
|
|
Term
How do peptide hormones and catecholamines circulate in the body? |
|
Definition
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|
Term
How do steroid/thyroid hormones circulate in the body? |
|
Definition
they are very hydrophobic and are carried in the blood bound to a variety of plasma proteins (eg albumin) |
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|
Term
Why do steroid/thyroid hormones have a longer lasting effect than peptide hormones? |
|
Definition
Hormones bound to proteins are cleared from the circulation much slower. This creates a reservoir of hormone in blood, minimising hormone fluctuations and extending the half life of hormone. |
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|
Term
How long does bound T4 circulate for? |
|
Definition
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|
Term
How long does free T4 circulate for? |
|
Definition
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|
Term
How are hydrophilic hormones transported and what is the benefit? |
|
Definition
dissolved in blood plasma free hormone is active form eg epiphrene |
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|
Term
How are hydrophobic hormones transported and what is the benefit? |
|
Definition
bound to plasma proteins prolonged half life eg T4 or cortisol |
|
|
Term
What are the functions of binding proteins? |
|
Definition
- help transport hormones and regulate the amount is biologicallt active - permits delivery to target site - protects hormones from degradation and excretion |
|
|
Term
Hormones are inactive until... |
|
Definition
...it dissociates from binding sites |
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|
Term
What are the general types of binding proteins and what do they transport? |
|
Definition
plasma albumins transport large proteins (thyroid and steroid hormones) transport globulins transport specifically (hormone binding proteins and steroid binding proteins) |
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|
Term
Describe the Michaelis-Menton kinetics of binding |
|
Definition
Association and dissociation of the hormone-protein complex is in equilibrium set by the concentrations of free hormone and binding sites |
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|
Term
What does the equation KD = Kd / Ka mean? |
|
Definition
overall rate of reaction = dissociation constant/association constant |
|
|
Term
What can the Michaelis-Menton equation be used to calculate? |
|
Definition
the conc of free hormone if the other parameters are known |
|
|
Term
What is the significance of the free hormone? |
|
Definition
- this is the concentration that is available for binding and regulates hormone release (via feedback control). - the amount the can be cleared from the circulation by the kidney and liver - the amount observed clinically in a case of over/underproduction |
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|
Term
How are hormones inactivated? |
|
Definition
either by their target tissue or by metabolism (in the liver and kidney) |
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|
Term
What occurs to hormones that escape degradation? |
|
Definition
excreted via the kidney into the urine except for hormones bound to plasma proteins (which cannot cross the renal filtration barrier) |
|
|
Term
Describe the receptors for a lipid soluble hormone |
|
Definition
inner or outer surface of the membrane |
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|
Term
Describe the receptors for a lipid insoluble hormone |
|
Definition
on the outer surface of the membrane |
|
|
Term
What must the hormone have if it does not have a direct action on the target cell? |
|
Definition
a secondary messenger system (eg cAMP or Ca2+) |
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|
Term
What follows the diffusion of steroid hormones across the membrane? |
|
Definition
1. diffusion through membrane lipids 2. binding of hormone to cytoplasmic/nuclear receptor 3. binding of hormone-receptor complex to DNA 4. gene activation 5. transcription and mRNA produced 6. translation and protein synthesis 7. alteration of cellular structure or activity 8. target cell response |
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|
Term
What follows the diffusion of thyroid hormones across the membrane? |
|
Definition
1. transport across plasma membrane 2. bind to receptors on the mitochondria and nucleus 3. bidning of hormone-receptor complex to DNA 4. gene activation 5. transcription and mRNA produced 6. translation and protein synthesis 7. alteration of cellular activity/increased ATP production 8. target cell response |
|
|
Term
What factors control hormone levels? |
|
Definition
- rate of secretion - amount of hormone transported bound to a carrier protein - rate at which hormone is metabolised |
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|
Term
What is hormone release dependent on? |
|
Definition
1. neural input 2. humoral input (blood bourne) a) stimulatory b) inhibitorary |
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|
Term
Describe the stress induced pathway that leads to the release of cortisol |
|
Definition
1. stress causes neural signals to the hypothalamus 2. increased secretion of CRH hormone 3. anterior pituitory gland 4. increased ACTH secretion 5. adrenal cortex 6. increased cortisol secretion |
|
|
Term
What are the 3 humoral signals? |
|
Definition
|
|
Term
How do hormones stimulate hormone release? |
|
Definition
- secreted form the hypothalamus or the anterior pituitary gland - act to stimulate/inhibit release of other hormones - negative feedback |
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|
Term
How do ions stimulate hormone release? EXAMPLE |
|
Definition
eg blood potassium levels in the kidneys control the amount of aldosterone |
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|
Term
How do metabolites stimulate hormone release? EXAMPLE |
|
Definition
eg glucose circulating in the blood determines the amount of insulin release by the beta cells in the pancreas to control blood glucose levels |
|
|
Term
|
Definition
the amount of energy expended per unit of time |
|
|
Term
What is metabolic rate influenced by? |
|
Definition
muscular activity age sex body surface area environmental temperature |
|
|
Term
What does energy balance = |
|
Definition
|
|
Term
|
Definition
Basal Metabolic Rate rate of energy expenditure of a person who is awake, lying down and mentally relaxed, fasted for 12 hours and in a thermoneutral environment (20 dc) |
|
|
Term
What is oxygen consumption a measure of? |
|
Definition
rate at which the individual is using oxygen (Lmin-1) |
|
|
Term
What is the energy equivalent of oxygen consumption? |
|
Definition
o2 for the food being metabolised (kJ per L of O2) |
|
|
Term
How is metabolic rate obtained? |
|
Definition
|
|
Term
|
Definition
instrument for measuring the air capacity of the lungs |
|
|
Term
What factors affect basal metabolic rate? |
|
Definition
body weight body surface area (higher = higher as more heat is lost) lean body mass (higher = higher) age (increases = decreases) sex (males are higher) pregnancy (increase) |
|
|
Term
What is the average metabolic rate? |
|
Definition
20-25kcal per kg of body weight per day |
|
|
Term
What factors affect general metabolic rate? |
|
Definition
exercise ingestion of food (protein increases) fever fasting and malnutrition sleep |
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|
Term
What hormones affect energy metabolism? |
|
Definition
catecholamines thyroid hormones growth hormones male sex hormones |
|
|
Term
How does our body know how to transition between the absorptive and the post absorptive state? |
|
Definition
- under control of the endocrine system (mainly pancreas) - islets of langerhans - acini produces digestive juices |
|
|
Term
What are the islets of langerhans? |
|
Definition
The pancreatic islets or islets of Langerhans are the regions of the pancreas that contain its endocrine (i.e., hormone-producing) cells. |
|
|
Term
What are the different islets of langerhans and what do they produce? |
|
Definition
alpha = glucagon beta = insulin gamma = somatostatin |
|
|
Term
|
Definition
promotes synthesis of energy storage molecules and other processes characteristic of the anabolic state. Plasma insulin levels trigger transition between anabolic and catabolic states |
|
|
Term
Describe the insulin secretion mechanism |
|
Definition
1. absorptive state 2. plasma glucose increases 3. plasma amino acid increases 4. increased GIP secretion 5. increased parasympathetic activity |
|
|
Term
What do increased plasma glucose, plasma amino acid and GIP secretion cause? |
|
Definition
pancreatic beta cells to secrete insulin |
|
|
Term
What is glucagon secreted by? |
|
Definition
|
|
Term
What does glucagon promote? |
|
Definition
process of catabolism when plasma glucose decreases |
|
|
Term
Describe the glucagon secretion mechanism |
|
Definition
1. decreased glucose 2. increased plasma amino acids 3. increased sympathetic activity |
|
|
Term
How are blood glucose levels controlled? |
|
Definition
negative feedback with glucagon and insulin |
|
|
Term
What is the desired blood glucose level? |
|
Definition
70-140mgdL-1 (4-8mmolL-1) |
|
|
Term
What happens if levels rise above 140mgdL-1? |
|
Definition
hyperglycaemia (diabetes mellitus) |
|
|
Term
What happens if levels fall below 60mgdL-1? |
|
Definition
|
|
Term
What do adrenal corticosteroids promote? glucose |
|
Definition
glycogen production and maintain glycogen reserves |
|
|
Term
What is growth hormone? glucose |
|
Definition
an anti-insulin glucose-sparing agent |
|
|
Term
What do catecholamines do? glucose |
|
Definition
when levels fall below 4mmol-1 they can mobilise glucose for use by brain |
|
|
Term
What do thyroid hormones do? glucose |
|
Definition
enhance glucose metabolism, ensure glucose reserves are mobilised |
|
|
Term
When is anabolic metabolic rate occurring? |
|
Definition
|
|
Term
When is catabolic metabolic rate occurring? |
|
Definition
|
|
Term
What controls the transition between anabolic and catabolic metabolic rate? |
|
Definition
pancreatic hormones insulin and glucagon |
|
|
Term
Glucose must be tightly regulated at ___ moles per L |
|
Definition
|
|
Term
What does increased insulin secretion from pancreatic beta cells have an effect on? |
|
Definition
most tissues liver and muscle |
|
|
Term
What effect does insulin have on most tissue? |
|
Definition
increased glucose uptake into cells therefore decreased plasma glucose |
|
|
Term
What effect does insulin have on liver and muscle? |
|
Definition
increased glycogen synthesis decreased glycogenolysis therefore decreased plasma glucose |
|
|
Term
What effect does insulin have on the liver? |
|
Definition
decreased gluconeogenesis therefore decreased plasma glucose |
|
|
Term
What is diabetes mellitus? |
|
Definition
excessive blood glucose by inadequate uptake by cells in body hyperglycaemic |
|
|
Term
What causes diabetes mellitus? |
|
Definition
impaired insulin secretion type 1 = beta cell destruction type 2 = impaired beta cell function and insulin resistance |
|
|
Term
Symptoms of diabetes mellitus: |
|
Definition
increased thirst increased urination tired (no glucose storage) weight loss |
|
|
Term
Later symptoms of diabetes mellitus: |
|
Definition
blurred visin slow wound healing general itching |
|
|
Term
|
Definition
beta cell destruction absolute insulin deficiency auto-immune idiopathic |
|
|
Term
|
Definition
insulin independent impaired insulin secretion and/or resistance to the action of insulin on target tissue |
|
|
Term
What is gestational diabetes? |
|
Definition
develops during pregnancy (can stop after birth or continue into type 2) |
|
|
Term
What are the diagnosis measurements for diabetes mellitus? |
|
Definition
urine glucose blood glucose glycated haemoglobin glycated serum proteins urine ketones other blood metabolite/hormones |
|
|
Term
How is type 1 diabetes managed? |
|
Definition
optimised/intensive therapy mimic exogenous insulin, administer around meal times administered subcataneously diet, exercise and education |
|
|
Term
How is type 2 diabetes managed? |
|
Definition
lifestyle modifications: - restrict fat and energy intake - encourage exercise - stop smoking |
|
|
Term
What are the 5 oral agents used to control Type 2? |
|
Definition
sulphonylureas thiasolidizediones biguanides alpha-glucosidase inhibitors agents that reduce fat absorption |
|
|
Term
How do sulphonylureas work? |
|
Definition
increase insulin secretion bind to receptor on beta cell, leading to closure of ATP-sensitive potassium channels. |
|
|
Term
What are sulphonylureas associated with? |
|
Definition
weight gain and beta cell failure |
|
|
Term
How do thiazolidizediones work? |
|
Definition
reduce insulin resistance. PPAR-y agonist. More costly. |
|
|
Term
|
Definition
reduces insulin resistance and can reduce hepatic glucose output eg metformin |
|
|
Term
How do alpha-glucosidase inhibitors work? |
|
Definition
delay absorption of carbohydrates. inhibit alpha-glucosidase and increase fibre in diet, can cause flatulance |
|
|
Term
How do agents that reduce fat absorption work? |
|
Definition
reduce weight inhibits pancreatic lipase serotonin and noradrenaline reuptake inhibitor |
|
|
Term
Describe the mechanism of sulphonylureas |
|
Definition
1. sulphonylureas binds to its receptor on the beta cell membrane 2. causes potassium channels to close 3. depolarisation 4. causes ca2+ channels to open 5. causes insulin release |
|
|
Term
How do potassium channels close? |
|
Definition
glucose molecule bind to a GLUT-2 receptor |
|
|
Term
Describe the mechanism of TZDs |
|
Definition
1. TZD enters cells and binds to PPAR-y (found in fat and liver cells) 2. these form a complex with RXR 3. leads to enhanced expression of insulin sensitive genes (eg GLUT4) 4. increase insulin sensitivity at target cell and enhance lipid storage |
|
|
Term
What is the treatment of type 2 diabetes? |
|
Definition
1. non pharmalogical therapy 2. singel oral agent 3. two oral agents 4. insulin and oral agent 5. full insulin replacement |
|
|
Term
How does the body respond to hypoglycaemia? |
|
Definition
glucagon released from alpha cells increased gluconeogenesis and glycogenolysis inhibition of insulin secretion |
|
|
Term
What are the symptoms and treatment of hypoglycaemia? |
|
Definition
- sweating, pounding heart, shaking, hunger, confusion, drowsiness, speech difficulty - oral glucose (IV if unconscious) - recovery in minutes |
|
|
Term
What are the longterm consequences of diabetes? |
|
Definition
- cataracts and retinography - higher risk of heart attacks/CV diseases/gastro diseases - prevents wound healing - demyelination of nerve - impaired kidney function leads to increased blood pressure |
|
|
Term
How do retinal capillaries change during diabetes? |
|
Definition
they are usually tight junctions however they widen and proteins can leak out |
|
|
Term
What is diabetic nephropathy? |
|
Definition
kidney disease caused by damage to the capillaries in the kidneys' glomeruli |
|
|
Term
What are the effects of diabetic nephropathy? |
|
Definition
- harder for kidneys to filter blood - increased blood pressure and hypertension - releases signalling pathways - causes ECM accumulation |
|
|
Term
What is diabetic neuropathy? |
|
Definition
nerve damage caused by chronically high blood sugar and diabetes occurs in patients in poorly controlled diabetes |
|
|
Term
What are the effects of diabetic neuropathy? |
|
Definition
uncomfortable symptoms in lowers legs nerve conduction velocity is slowed at this time distal symmetrical neuropathy demylenination of the nerves |
|
|
Term
What are the future directions in diabetes research and treatment? |
|
Definition
- pancreas and islet cell transplantation - stem cell therapy - gene therapy |
|
|
Term
How do genetics affect growth and development? |
|
Definition
usually set the overall height, patterns and timings of growth spurts |
|
|
Term
How does the environment affect growth and development? |
|
Definition
mainly nutritional, although illness, trauma and even smoking can modify growth processes |
|
|
Term
What can ultrasound technology measure? |
|
Definition
- foetal growth throughout pregnancy - abdominal circumference - femur length - biparietal diameter (ear to ear) |
|
|
Term
____ weeks gestation shows the greatest increase in foetal length |
|
Definition
|
|
Term
What changes occur during periods of growth? |
|
Definition
- increase in size and number of cells in bodys soft tissue - increase in length and thickness of bone |
|
|
Term
What does bone act as a reserve for? |
|
Definition
calcium for when plasma calcium declines |
|
|
Term
|
Definition
|
|
Term
What gives bone its strength? |
|
Definition
crystals of calcium phosphate-hydroxyapatite |
|
|
Term
What kind of tissue is bone? |
|
Definition
bone is a dynamic living tissue allowing it to regenerate in cases of fracture but also to let the bone develop and grow when under the influence of hormones |
|
|
Term
What does bone consist of? |
|
Definition
osteoblasts osteocytes osteoclasts osteoid calcium and phosphate crystals |
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|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
secrete enzymes for remodelling (breakdown bone tissue) |
|
|
Term
|
Definition
|
|
Term
|
Definition
1. skeleton is laid down as cartilage model 2. model replaced by bone (ossification) |
|
|
Term
Where does growth stature largely occur? |
|
Definition
through an increase in length of long bones in limbs |
|
|
Term
Where does the addition of new growth material take place? |
|
Definition
at the epiphyseal growth plates which lie between the main shaft of the bone and 2 ends |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
What are the epiphyseal growth plates? |
|
Definition
lie between the 2 stem cells (chondroblasts) lie between the plates |
|
|
Term
|
Definition
begins in the innermost layer, osteogenic cells differentiate into osteoblasts that secrete osteoid and lay down bone |
|
|
Term
Where is growth hormone derived from? |
|
Definition
the pituitary samototrophs |
|
|
Term
What is GH secretion controlled by? |
|
Definition
GHRH which stimulates output somatostatin inhibits it |
|
|
Term
Describe GH release pattern? |
|
Definition
irregular pulsatile pattern of release influenced by physiological stimuli (eg stress, exercise and significantly deep sleep in children) |
|
|
Term
What can stimulate early development in girls? |
|
Definition
|
|
Term
What effect does insulin have on GH secretion? |
|
Definition
|
|
Term
What are the major metabolic effects of GH? |
|
Definition
- opposes insulin effects - acts on liver, muscle and adipocytes - depresses glucose metabolism preserving for use by CNS - stimulates lipolysis |
|
|
Term
How does GH promote growth? |
|
Definition
- acts directly on chondrocytes and increase rate of differentation and cartilage formation - indirect effects using other growth fcators (eg IGF) which act on cartilage, fat cells, fibroblasts and humour cells |
|
|
Term
What are the abnormal effects of GH secretion? |
|
Definition
dwarfism gigantism acromegaly |
|
|
Term
|
Definition
deficient secretion of GH can be due to defective GH receptors |
|
|
Term
What are the effects of dwarfism? |
|
Definition
- stunting of growth - poor muscle development - higher than normal body fat |
|
|
Term
|
Definition
excessive secretion of GH before puberty |
|
|
Term
What are the effects of gigantism? |
|
Definition
|
|
Term
|
Definition
excessive secretion of GH in adulthood from pituitary tumours |
|
|
Term
What are the effects of acromegaly? |
|
Definition
overgrowth of soft tissue and increase in bone circumference |
|
|
Term
What other hormones affect growth? |
|
Definition
thyroid hormone corticosteroids insulin Vt D and parathyroid hormone |
|
|
Term
What does Human Growth Hormone (hGH) do? |
|
Definition
- grow in stature and bone growth - orchestrate nutrient partitioning (moves energy to protein synthesis rather than fat) |
|
|
Term
What are the actions of hGH? |
|
Definition
- improves muscle definition - elongate bone - decrease glucose storage - decrease fat storage - decreases fat mass (adipose tissue) - exercise has the effects of hGH levels |
|
|
Term
|
Definition
peptide injected synthetic can be artificially stimulated |
|
|
Term
Why do athletes abuse hGH? |
|
Definition
- increase muscle mass and strength - increase lean body mass - improve appearance of musculature - increase final adult height |
|
|
Term
Where is the thyroid gland located? |
|
Definition
on the ventral side of the trachea |
|
|
Term
What hormones does the thyroid secrete? |
|
Definition
|
|
Term
|
Definition
regulate the body's metabolic rate |
|
|
Term
What is on the posterior side of the thyroid gland? |
|
Definition
4 parathyroid glands that secrete parathyroid hormones |
|
|
Term
What cells make up thyroid tissue? |
|
Definition
follicular cells and parafollicular cells (c cells) |
|
|
Term
What do follicular cells secrete? |
|
Definition
iodine-containing thyroid hormones. They consist of thyroxine (T4) and triiodothyronine (T3) |
|
|
Term
What do parafollicular (c) cells secrete? |
|
Definition
|
|
Term
What do follicle cells surround? |
|
Definition
a follicle cavity that holds a viscous colloid, a fluid containing a large quantity of dissolved proteins |
|
|
Term
What globular protein do follicle cells synthesise? |
|
Definition
thyroglobulin and secrete it into the colloid. contains tyrosine |
|
|
Term
How are iodide ions related? |
|
Definition
they are absorbed from the diet and delivered to the thyroid TSH sensitive carrier proteins on the basal membrane of the follicle cells transport iodide ions into the cytoplasm |
|
|
Term
What is the fate of iodide ions in the cytoplasm? |
|
Definition
they diffuse to the apical surface and lose an electron by thyroid peroxidase and attach to the tyrosine portion of a thyroglobulin molecule within the follicle cavity |
|
|
Term
What is the fate of tyrosine molecules with attached iodide ions? |
|
Definition
they become crosslinked by covalent bonds and form molecules of thyroid hormones that remain incorporated into thyroglobulin. |
|
|
Term
How many iodide atoms does thyroxine and triiodothyronine contain? |
|
Definition
|
|
Term
What is the major factor controlling thyroid hormone release and why? |
|
Definition
concentration of TSH in the circulating blood TSH stimulates iodide transport into the follicle cells and stimulates production of thyroglobulin and thyroid peroxidase as well as thyroid hormone re;ease |
|
|
Term
What events occur in the presence of TSH? |
|
Definition
1. follicle cells remove thyroglobulin from the follicles by endocytosis 2. lysosomal enzymes break down the thyroglobulin and the amino acids and thyroid hormones enter the cytoplasm. amino acids are recycled and used to make more thyroglobulin |
|
|
Term
Which is produced more T3 or T4? |
|
Definition
T4 is produced at 10x greater rate than T3 |
|
|
Term
|
Definition
T3 is 4x more potent than T4 |
|
|
Term
What is the fate of secreted T4? |
|
Definition
T4 secreted in plasma eventually converted by liver, kidney or target tissues to more active T3 |
|
|
Term
Describe the events that cause T3 and T4 secretion |
|
Definition
1. stress or cold temp in children 2. hypothalamus increases TRH secretion 3. anterior pituitary increased TSH secretion 4. thyroid increased T3 secretion |
|
|
Term
|
Definition
negative feedback loop between T4 levels and hypothalamus and anterior pituitary |
|
|
Term
What effect does increased plasma T3 have on tissues? |
|
Definition
- increased BMR - increased heat production - increased responsiveness to sympathetic input - permits normal growth and development |
|
|
Term
What effect does increased plasma T3 have on the nervous system? |
|
Definition
- permits normal growth and development - permits maintenance of normal activity |
|
|
Term
How do thyroid hormones act? |
|
Definition
1. thyroid hormone 2. intracellular receptor 3. transcription of specific genes 4. increased protein synthesis (cell growth and maturation) 5. increased cellular respiration 6. increased o2 consumption and metabolic rate 7. increased CO and ventilation and increased thermogenesis |
|
|
Term
What do increased cell growth and maturation and increased cellular respiration cause? |
|
Definition
|
|
Term
What are the effects of thyroid hormones on peripheral tissues? |
|
Definition
- elevated rate of o2 and energy consumption - increased HR and force of contraction (increased BP) - increased sympathetic stimulation sensitivity - maintenance of normal sensitivity to changes of o2 and co2 - stimulation of RBC formation and enhanced o2 delivery - stimulation of activity in other endocrine tissues - accelerated turnover of minerals in bone |
|
|
Term
What are some thyroid gland disorders? |
|
Definition
Hypothydroidism Hyperthyroidism Thyroid nodules |
|
|
Term
What is hypothyroidism? give examples |
|
Definition
underactive thyroid - myxoedema: swelling of the skin - hashimoto's thyroiditis: immune system attacks thyroid |
|
|
Term
Common symptoms of hypothyroidism |
|
Definition
fatigue weight gain feeling cold dry skin and hair heavy menstural periods constipation slowed thinking |
|
|
Term
How is hypothyroidism diagnosed? |
|
Definition
elevated level of serum TSH |
|
|
Term
How is hypothyroidism treated? |
|
Definition
replacement therapy - thyroxine (oral) - T3 (oral) - thyroid hormone in pill form daily
overdose: angina and cardiac dysrhrythmia/hyperthyroidism |
|
|
Term
What is hyperthyroidism? give examples |
|
Definition
overactive thyroid Graves disease |
|
|
Term
Common symptoms of hyperthyroidism |
|
Definition
jitterness/shaking rapid heart beat feeling hot weight loss fatigue frequent bowel movements shorter/lighter menstural periods |
|
|
Term
How is hyperthyroidism diagnosed? |
|
Definition
easily confused with other disorders if not diagnosed right away analyse elevated level of free T4 and low level of TSH in the blood |
|
|
Term
How is hyperthyroidism treated? |
|
Definition
- surgical - beta blockers eg propanolol - antithyroid drugs - iodide - radioiodide |
|
|
Term
Where is 99% of calcium found and in what form? |
|
Definition
in bones in the form calcium phosphate (salt) |
|
|
Term
How is calcium mobilised? |
|
Definition
|
|
Term
What is calcium important in? |
|
Definition
teeth connective tissue blood clotting functions like messenger systems |
|
|
Term
What hormones control calcium? |
|
Definition
Parathyroid hormone (PTH) Calcitonin Vit D (cholecalciferol) converted in calcitriol |
|
|
Term
Where are calcitonin and PTH secreted from? |
|
Definition
PTH from the parathyroid gland Calcitonin from the thyroid gland |
|
|
Term
What sites control calcium levels and how? |
|
Definition
bones: release calcium into plasma or reabsorb digestive tract: release more ca2+ from diet kidneys: increase excretion/absorption |
|
|
Term
What is the intracellular free calcium concentration |
|
Definition
|
|
Term
What is the total intracellular calcium concentration (free and bound) |
|
Definition
|
|
Term
What is the extracellular calcium conc? |
|
Definition
|
|
Term
What factors increase blood calcium levels? |
|
Definition
- PTH (with calcitriol - PTH |
|
|
Term
How does PTH (with calcitriol) control blood calcium levels? |
|
Definition
higher concentrations increase rate of intestinal absorption and vice versa |
|
|
Term
How does PTH increase blood calcium levels? |
|
Definition
Bone: osteoclasts stimulated to release stored calcium ions from bone KIdney: retain lost calcium ions |
|
|
Term
What factors decrease blood calcium levels? |
|
Definition
- decreased PTH (with calcitriol): rate of intestinal absorption decrease - calcitonin |
|
|
Term
How does calcitonin decrease blood calcium levels? |
|
Definition
kidneys allow calcium loss bone: osteoclasts inhibited while osteoblasts continue to lock calcium ion in bone matrix |
|
|
Term
Where are the 4 parathyroid glands? |
|
Definition
|
|
Term
Describe the cell types found in the parathyroid |
|
Definition
Cheif/principle cells that secrete PTH and monitor Ca2+ levels Oxiphil cells (function unknown) |
|
|
Term
|
Definition
Mobilises calcium from bone Reabsorption of Ca2+ at the kidneys Calcitrol at the kidneys |
|
|
Term
Where is calcitronin released from? |
|
Definition
c cells of the thyroid when Ca2+ levels rise |
|
|
Term
How does calcitonin cause a drop in Ca2+ conc? |
|
Definition
inhibition of osteoclasts stimulation of ca2+ excretion at the kidneys |
|
|
Term
|
Definition
Calcitriol is a form of vitamin D. It works by promoting proper absorption and use of calcium and phosphate by the body in normal bone development and maintenance.
steroid hormone that works alongside PTH |
|
|
Term
How is calcitriol initially synthesised? |
|
Definition
from Vit D3 by 7dehydrocholesterol in sunlight |
|
|
Term
How does calcitriol increase calcium levels? |
|
Definition
- increases calcium levels by stimulating calcium absorption from digestive tract - works on the distal tubule of the kidney to reabsorb ca2+ |
|
|
Term
Which foods are rich in vit d3? |
|
Definition
mushrooms certain oily fish (mackrel, salmon) eggs beef, liver added to most western milk products |
|
|
Term
What must be present for calcitriol to be synthesised in the kidney? |
|
Definition
|
|
Term
What does calcitriol act on? |
|
Definition
|
|
Term
Which hormone controls calcium absorption? |
|
Definition
|
|
Term
Which hormones affect calcium blood levels using bone? |
|
Definition
Calcitonin (calcification) Resorption from bone to blood (PTH and calcitriol) |
|
|
Term
How is calcium controlled by the kidneys? |
|
Definition
filtered from the blood into the kidneys PTH stimulated reabsorption into blood Calcitonin inhibits reabsorption into blood |
|
|
Term
At what serum calcium concentration would a patient be hypercalcemic? |
|
Definition
|
|
Term
What are the causes of hypercalcaemia? |
|
Definition
|
|
Term
What are the symptoms of hypercalcaemia? |
|
Definition
fatigue confusion cardiac arrhythmias calcification of kidneys and soft tissues |
|
|
Term
What is the treatment of hypercalcaemia? |
|
Definition
infusion of hypotonic fluid to lower ca2+ levels remove parathyroid gland administer calcitonin |
|
|
Term
At what serum calcium concentration would a patient be hypocalcemic? |
|
Definition
(<2.1 mmol L-1) much less common |
|
|
Term
What are the causes of hypocalcaemia? |
|
Definition
hypothydoidism under secretion of PTH Vit D deficiency chronic renal failure |
|
|
Term
What are the symptoms of hypocalcaemia? |
|
Definition
muscle spasms convulsions weak heartbeats cardiac arrhtyhmias osteoporosis |
|
|
Term
What is the treatment of hypocalcaemia? |
|
Definition
include calcium supplements administer vit D |
|
|
Term
What is phosphate balance linked to? |
|
Definition
|
|
Term
Phosphate skeleton statistic pls... |
|
Definition
740g of PO43- is bound in mineral salts of skeleton |
|
|
Term
PO43- concentration of plasma is... |
|
Definition
|
|
Term
Where is phosphate reabsorbed? |
|
Definition
kidney (proximal convoluted tubule) |
|
|
Term
What is phosphate stimulated by? |
|
Definition
|
|
Term
What are the causes of hyperphosphatemia? |
|
Definition
high dietry phosphate intake hyperparathyroidism |
|
|
Term
What are the symptoms of hyperphosphatemia? |
|
Definition
no immediate symptoms chronic elevation leads to calcification of soft tissue |
|
|
Term
What are the treatments of hyperphosphatemia? |
|
Definition
with dietry reduction or PTH supplements |
|
|
Term
What are the causes of hypophosphatemia? |
|
Definition
poor diet kidney disease malabsorption syndrome hyperparathyroidism Vit D deficiency |
|
|
Term
What are the symptoms of hypophosphatemia? |
|
Definition
anorexia dizziness muscle weakness cardiomyopathy osteoporosis |
|
|
Term
What are the treatments of hypophosphatemia? |
|
Definition
dietry improvement Vit D or calcitriol supplementation |
|
|
Term
How does decreased Ca2+ affect phosphate via bone? |
|
Definition
1. PTH secreted 2. osteoclast activity increases therefore increase blood phosphate conc |
|
|
Term
How does decreased Ca2+ affect phosphate via kidney? |
|
Definition
1. PTH secreted 2. phosphate secretion from renal tubules therefore decreased conc |
|
|
Term
Therefore how does decreased ca2+ affect phosphate overall? |
|
Definition
overall normal balanced conc |
|
|
Term
Where is the pituitary gland ? |
|
Definition
- pea sized structure that sits inferiorly to the hypothalamus - near the optic nerve |
|
|
Term
What does the pituitary gland form? |
|
Definition
part of the posterior forebrain |
|
|
Term
Where does the pituitary gland with respect to the pons? |
|
Definition
|
|
Term
Where does the pituitary gland with respect to the forebrain? |
|
Definition
|
|
Term
Where does the pituitary gland with respect to the hypothalamus? |
|
Definition
inferiorly and is connected |
|
|
Term
Where does the pituitary gland with respect to the sphenoid bone? |
|
Definition
within the sphenoid bone in a cavity called sella tuncica |
|
|
Term
What is the neurohypophysis also known as? |
|
Definition
|
|
Term
What does the neurohypophysis consist of? |
|
Definition
the median eminence (neural tissue of the hypothalamus), the posterior pituitary itself and infundibular system (which connects the two) |
|
|
Term
What is the adenohypophysis also known as? |
|
Definition
|
|
Term
What does the adenohypophysis consist of? |
|
Definition
two portions: - anterior pituitary itself (also called pas distalis) - smaller pas tuberalis which wraps around the infundibulum |
|
|
Term
What forms a boundary between the anterior and posterior pituitary? |
|
Definition
- pars intermedia - actively secretes MSH during development |
|
|
Term
How does the pars intermedia change after birth? |
|
Definition
regresses and may be absent in adult gland |
|
|
Term
When does the pituitary develop? |
|
Definition
third trimester of gestation |
|
|
Term
Describe the basic development of the pituitary (4 steps) |
|
Definition
1. roof of the mouth lies close to the 3rd ventricle of the brain and they bulge towards each other 2. buccal cavity (roof of mouth) bulges upwards to form Rathke's pouch 3. neural ectoderm bulges downward to form infundibulum 4. Rathke's pouch 'pinches off' and folds around the infundibulum |
|
|
Term
Which tissue forms the posterior pituitary and which tissue forms the anterior pituitary? |
|
Definition
Neural tissue forms posterior pituitary Non-neural tssue forms the anterior pituitary |
|
|
Term
What causes the anterior pituitary to release its hormones? |
|
Definition
1. neurosecretory neurones in the hypothalamus release hormones into the hypophysial portal system 2. these stimulate the endocrine cells of the anterior pituitary to release hormones |
|
|
Term
How many hormones does the anterior pituitary release? |
|
Definition
|
|
Term
What kind of blood supply does the AP have? |
|
Definition
|
|
Term
Where does the AP receive its blood supply from? |
|
Definition
the superior hypophyseal artery comes into the median emminence of the hypothalamus where the capillary bed is closely related to the neurosecretory neurones of the hypothalamus |
|
|
Term
Where are hypothamic hormones released into? |
|
Definition
the capillary bed and then carried to another set of capillaries in the hypothalamic-hypophyseal system (in the AP) |
|
|
Term
What is the hypothalamic hypophyseal portal system? |
|
Definition
The hypophyseal portal system is a system of blood vessels in the brain that connects the hypothalamus with the anterior pituitary. Its main function is the transport and exchange of hormones to allow a fast communication between both glands. |
|
|
Term
List the main hormones of the anterior pituitary gland |
|
Definition
Growth hormone (GH) Prolactin (PRL) Thyroid stimulating hormone (TSH) Follicle stimulating hormone (FSH) Luteinizing hormone (LH) Corticotropin related peptide hormones |
|
|
Term
|
Definition
by somatotroph and lactotroph cells
single peptide chain |
|
|
Term
What are the effects of GH? |
|
Definition
produces powerful effects on growth and metabolism in most peripheral tissues except CNS |
|
|
Term
Where is PRL synthesised? |
|
Definition
by somatotroph and lactotroph cells
single peptide chain |
|
|
Term
What are the effects of PRL? |
|
Definition
weak somatotrophic effects promotes growth and maturation of mammary gland during pregnancy to prepare it for milk secretion |
|
|
Term
|
Definition
glycoprotein hormone regulates function of thyroid gland |
|
|
Term
What are the roles of FSH and LH? |
|
Definition
gonadrotrophic hormones important roles in spermatogenesis by the testes and production of sex hormone in both sexes |
|
|
Term
Name some corticotropin related hormones and how are they derived? |
|
Definition
ACTH and MSH derived from a single common precursor |
|
|
Term
What controls the release of hormones from the anterior pituitary? |
|
Definition
|
|
Term
Where are specific hormones of the anterior pituitary synthesised? |
|
Definition
in the cell bodies of neurones in discrete areas of the median eminence |
|
|
Term
Describe the hormone chain that releases thyroid hormones to target tissues |
|
Definition
HH: Thyrotropin-releasing hormone (TRH) APH: Thyroid-stimulating hormone (TSH) Endocrine target: Thyroid gland |
|
|
Term
Describe the hormone chain that releases cortisol to target tissues |
|
Definition
HH: Corticotropin-releasing hormone (CRH APH: Adrenocorticotropic hormone Endocrine target: Adrenal cortex |
|
|
Term
Describe the hormone chain that releases growth hormone to target tissues |
|
Definition
HH: Growth hormone–releasing hormone (GHRH) APH: Growth hormone Endocrine target: Liver releases Insulin-like growth factor |
|
|
Term
Describe the hormone chain that releases adrogens, estrogens and progesterone to target tissues and germ cells of the gonads |
|
Definition
HH: Gonadotropin-releasing hormone (GnRH) APH: FSH and LH Endocrine target: Endocrine cells of the gonads |
|
|
Term
Describe the hormone chain that releases prolactin the the breasts |
|
Definition
HH: Prolactin-releasing hormone PRH and Thyrotropin-releasing hormone (TRH) APH: prolactin |
|
|
Term
What hormone inhibits the release of prolactin? |
|
Definition
|
|
Term
What hormone inhibits the release of growth hormone? |
|
Definition
Somatostatin, also known as growth hormone–inhibiting hormone (GHIH) |
|
|
Term
Describe the negative feedback control of anterior pituitary hormones |
|
Definition
1. hypothalamic releasing hormones stimulate release of AP hormones 2. this stimulates the release of a hormone from an endocrine organ 3. hormone released from endocrine affects it target organ 4. response is switched off by that endocrine organ inhibiting release of AP hormone and release of hypothalamic hormone |
|
|
Term
How is the control of growth hormone different? |
|
Definition
GH release is controlled by a releasing and inhibiting hormone |
|
|
Term
What causes the posterior pituitary to release its hormone? |
|
Definition
neurosecretatory neurones in the hypothalamus send axons into the posterior pituitary. They release hormones within the PP, directing into the blood stream. |
|
|
Term
What hormones does the PP produce? |
|
Definition
ADH (arginine vasopressin) oxytocin both nonapeptides |
|
|
Term
How are PP hormones synthesised? |
|
Definition
by magnocellular neurones in the the supraoptic (SON) and paraventricular nuclei (PVN) of the hypothalamus |
|
|
Term
How are PP hormones transported? |
|
Definition
in association with specific carrier proteins (neurophysins) along the axons of these neurones to the nerve terminals within the posterior lobe |
|
|
Term
How are PP hormones released? |
|
Definition
hormones are stored in secretatory granules either in terminals or in varicosities (Herring bodies) that are distributed along the axon. Hormones are released b ca2+ dependent exocytosis into the capillaries |
|
|
Term
How do the structures of oxytocin (OT) and vasopressin (AVP) compare? |
|
Definition
They only differ in their amino acid compositions at position 3 and 8 |
|
|
Term
What amino acid is at position 8 in AVP and which physiological action is this responsible for? |
|
Definition
The arginine at position 8 in AVP is critical for its anti-diuretic action. |
|
|
Term
What amino acid is at position 8 in OT and which physiological action is this responsible for? |
|
Definition
The leucine substitution at position 8 in oxytocin does not remove all antidiuretic activity however, and at high doses oxytocin does stimulate water reabsorption by the kidney. |
|
|
Term
How does desmopressin, a synthetic derivative, compare to vasopressin? |
|
Definition
the N-terminal cystine is deaminated and the L-arginine at position 8 is replaced by the D form. These modifications extend the half life of the hormone when administered exogenously |
|
|
Term
What causes release of vasopressin? |
|
Definition
- increase in plasma osmotic pressure - decrease in plasma volume (dehydration) detected by osmoreceptors in hypothalamus |
|
|
Term
What receptors do ADH act on? |
|
Definition
|
|
Term
Where are V1 receptors found and what do they do? |
|
Definition
in vascular smooth muscle where it stimulates contraction via phosphoionositide turnover thereby increasin intracellular ca2+ |
|
|
Term
Where are V2 receptors found and what do they do? |
|
Definition
renal epithelial cells of the distal nephron to stimulate water reabsorption acts via cAMP |
|
|
Term
Describe the negative feedback system of ADH release |
|
Definition
1. changes detected by osmoreceptors in hypothalamus 2. stimulates release of ADH from pituitary 3. leads to increased water reabsorption by the kidneys and plasma dilution 4. decreased osmolarity feeds back into hypothalamus to decrease ADH release |
|
|
Term
What receptors does OT act on? |
|
Definition
oxytocin receptors act via phosphoinosotide turnover and ca2+ in myoepithelial cells of the mammary gland to contract and cause milk ejection |
|
|
Term
What role does oxytocin play? |
|
Definition
- stimulates ejection of milk and may play a role in expelling the foetus and placenta during labour - may play a role in erection, ejaculation and sperm progression |
|
|
Term
What is the stimulus for oxytocin release? |
|
Definition
- mechanical stimulation of the nipple (suckling) - afferent info travels via the spinothalamic tract and brainstem |
|
|
Term
What could abnormally high or low levels of a peripheral hormone be caused by? |
|
Definition
1. the peripheral gland (primary endocrine disease) 2. the pituitary gland (secondary endocrine disease) 3. the hypothalamus (tertiary endocrine disease) |
|
|
Term
What could one of the peripheral glands be? |
|
Definition
thryoid adrenal cortex gonads liver |
|
|
Term
Why are primary deficiencies the most severe? |
|
Definition
they involve complete absence of the peripheral hormone |
|
|
Term
What does the hypothalamus and the pituitary control? |
|
Definition
the normal secretion of thyroid hormones which in turn control metabolism |
|
|
Term
|
Definition
the thyroid cells do not produce sufficient amount of thyroid hormone which causes a decrease in metabolism and a build up of metabolites |
|
|
Term
What metabolites build up in hypothyroidism? |
|
Definition
glycosaminoglycans (sugar and protein compounds) |
|
|
Term
Where do glycosaminoglycans build up and why is this a problem? |
|
Definition
they build up inside of various organs and tissues and cause an increase in water and mucus which forms oedema |
|
|
Term
Describe the thyroid mechanism for the release of T3 and T4 |
|
Definition
1. hypothalamus releases TRH into portal system 2. TRH acts on the cells of the AP to release TSH which is transported via blood to the thyroid gland 3. thyroid releases T3 and T4 |
|
|
Term
What causes central hypothyroidism |
|
Definition
Tumour: usually pituitary adenoma (congenital or aquired) Radiation: causes damage to pituitary (usually caused by radiation therapy) Vascular disease: eg Sheehan syndrome that results in reduced TSH |
|
|
Term
What are some non-classic causes of hypothyroidism |
|
Definition
traumatic brain injury drug induced growth hormone therpay |
|
|
Term
What is central hypothyroidism a consequence of? |
|
Definition
changes to the pituitary rather than the thyroid itself |
|
|
Term
What would be the diagnosis if there were low T4 and low TSH levels? |
|
Definition
secondary disorder (pituitary) |
|
|
Term
|
Definition
pulsative during day and night deep sleep is a potent stimulus to GH secretion |
|
|
Term
What are the targets and effects of GH? |
|
Definition
to oppose those of insulin Muscle - decrease glucose uptake Adipose tissue - increase lipolysis Liver - increase gluconeogenesis Combined - insulin resistance |
|
|
Term
What characteristics do patients with GH-producing tumours have? |
|
Definition
usually insulin resistant glucose intolerant possibly diabetic |
|
|
Term
What does GH deficiency in children usually cause? |
|
Definition
pituitary dwarfism lack of GHRD or failure of IGF generation/action |
|
|
Term
How does the role of IGF change through age? |
|
Definition
During puberty there is a good correspondence between IGF and growth In adulthood there is no longitudal growth, GH and IGF play a role in regulation of body mass (anabolism) |
|
|
Term
How can GH secretion be tested? |
|
Definition
administering a GHRH analogue to stimulate GH release from pituitary (sermorelin) |
|
|
Term
Describe the mechanism of GH release |
|
Definition
1. GHRF released from hypothalamus (as is somatostatin) 2. Gh released from the pituitary 3. IGF-1 released from the liver to the peripheral tissue |
|
|
Term
What does excessive GH release in children cause? |
|
Definition
|
|
Term
What does excessive GH release in adults cause? |
|
Definition
acromegaly caused by a benign pituitary tumour |
|
|
Term
How is the condition ameliorated? |
|
Definition
- octreotide (a peptide analogue of somatostatin) - bromocriptine (dopamine agonist) - surgical removal or irridation of the tumour |
|
|
Term
Describe the usual pathway for prolactin release |
|
Definition
1. suckling 2. neural reflexes from the breast may initiate the release of a prolactin releasing factor (TRH?) for which there are mammatroph receptors 3. elevated levels of prolactin stimulate release of dopamine, which inhibits prolactin secretion |
|
|
Term
Why is prolactin secretion from the AP unusual? |
|
Definition
prolactin is subject to tonic inhibitory control by the hypothalamus. The inhibitory influence is via the so called dopaminergic-tuberohypophyseal pathway |
|
|
Term
How can prolactin levels be increaseD? |
|
Definition
by blocking dopamine receptors as prolactin release inhibition factor is dopamine |
|
|
Term
|
Definition
gonadotrophin-release hormone controls the release of gonadotrophins FSH and LH |
|
|
Term
|
Definition
controlled by neural input and by negative feedback of sex steroids by females |
|
|
Term
|
Definition
synthetic GnRH When given continuously they inhibit gonadotrophin release or if they are given in pulses they stimulate |
|
|
Term
What do gonadrelin agonist treat? |
|
Definition
endometriosis short term: prevent endogenous ovulation (for IVF) |
|
|
Term
What do gonadrelin antagonist treat? |
|
Definition
used in oncology to reduce the amount of testosterone (prostate cancer) |
|
|
Term
|
Definition
a testosterone derivative that inhibits the release of gonadotrophins. It is used where decreased sex hormone production would be beneficial e.g. endometriosis |
|
|
Term
What do clomiphene and cyclofenil do? |
|
Definition
inhibit the release stimulate the release gonadotrophin release by antagonizing the negative feedback effects of androgens and oestrogen |
|
|
Term
Generally what causes diabetes insipidus? |
|
Definition
ADH deficiency central vs nephrogenic |
|
|
Term
What causes central diabetes insipidus? |
|
Definition
loss of pituitary secretion of ADH |
|
|
Term
How is central diabetes insipidus treated? |
|
Definition
desmopressin (ADH analogue) whicih has higher V2 receptor selectivity and half life |
|
|
Term
What causes nephrogenic diabetes insipidus? |
|
Definition
impaired response to ADH at renal collecting duct |
|
|
Term
How is nephrogenic diabetes insipidus treated? |
|
Definition
fluid replacement until primary cause (eg effects of other drugs) are alleviated |
|
|
Term
|
Definition
Syndrome of inappropriate ADH secretion ADH secreting tumours, CHS disorders, pulmonary disorders and drug side effects |
|
|
Term
|
Definition
Demeclocycline = tetracycline antibiotic that blocks ADH binding Tolvaptan = unrelated V2 antagonist |
|
|
Term
Name an oxytocin agonist and what it is used for |
|
Definition
Carbetocin used to induce/augment labour and treat post-partum haemorrhage |
|
|
Term
Name an oxytocin antagonist and what it is used for |
|
Definition
Atosiban and barusiban reduce myometrial contractions and therefore treat preterm labour |
|
|
Term
What does GH deficiency in children usually cause? |
|
Definition
pituitary dwarfism lack of GHRD or failure of IGF generation/action |
|
|
Term
How does the role of IGF change through age? |
|
Definition
During puberty there is a good correspondence between IGF and growth In adulthood there is no longitudal growth, GH and IGF play a role in regulation of body mass (anabolism) |
|
|
Term
How can GH secretion be tested? |
|
Definition
administering a GHRH analogue to stimulate GH release from pituitary (sermorelin) |
|
|
Term
Describe the mechanism of GH release |
|
Definition
1. GHRF released from hypothalamus (as is somatostatin) 2. Gh released from the pituitary 3. IGF-1 released from the liver to the peripheral tissue |
|
|
Term
What does excessive GH release in children cause? |
|
Definition
|
|
Term
What does excessive GH release in adults cause? |
|
Definition
acromegaly caused by a benign pituitary tumour |
|
|
Term
How is the condition ameliorated? |
|
Definition
- octreotide (a peptide analogue of somatostatin) - bromocriptine (dopamine agonist) - surgical removal or irridation of the tumour |
|
|
Term
Describe the usual pathway for prolactin release |
|
Definition
1. suckling 2. neural reflexes from the breast may initiate the release of a prolactin releasing factor (TRH?) for which there are mammatroph receptors 3. elevated levels of prolactin stimulate release of dopamine, which inhibits prolactin secretion |
|
|
Term
Why is prolactin secretion from the AP unusual? |
|
Definition
prolactin is subject to tonic inhibitory control by the hypothalamus. The inhibitory influence is via the so called dopaminergic-tuberohypophyseal pathway |
|
|
Term
How can prolactin levels be increaseD? |
|
Definition
by blocking dopamine receptors as prolactin release inhibition factor is dopamine |
|
|
Term
|
Definition
gonadotrophin-release hormone controls the release of gonadotrophins FSH and LH |
|
|
Term
|
Definition
controlled by neural input and by negative feedback of sex steroids by females |
|
|
Term
|
Definition
synthetic GnRH When given continuously they inhibit gonadotrophin release or if they are given in pulses they stimulate |
|
|
Term
What do gonadrelin agonist treat? |
|
Definition
endometriosis short term: prevent endogenous ovulation (for IVF) |
|
|
Term
What do gonadrelin antagonist treat? |
|
Definition
used in oncology to reduce the amount of testosterone (prostate cancer) |
|
|
Term
|
Definition
a testosterone derivative that inhibits the release of gonadotrophins. It is used where decreased sex hormone production would be beneficial e.g. endometriosis |
|
|
Term
What do clomiphene and cyclofenil do? |
|
Definition
inhibit the release stimulate the release gonadotrophin release by antagonizing the negative feedback effects of androgens and oestrogen |
|
|
Term
Generally what causes diabetes insipidus? |
|
Definition
ADH deficiency central vs nephrogenic |
|
|
Term
What causes central diabetes insipidus? |
|
Definition
loss of pituitary secretion of ADH |
|
|
Term
How is central diabetes insipidus treated? |
|
Definition
desmopressin (ADH analogue) whicih has higher V2 receptor selectivity and half life |
|
|
Term
What causes nephrogenic diabetes insipidus? |
|
Definition
impaired response to ADH at renal collecting duct |
|
|
Term
How is nephrogenic diabetes insipidus treated? |
|
Definition
fluid replacement until primary cause (eg effects of other drugs) are alleviated |
|
|
Term
|
Definition
Syndrome of inappropriate ADH secretion ADH secreting tumours, CHS disorders, pulmonary disorders and drug side effects |
|
|
Term
|
Definition
Demeclocycline = tetracycline antibiotic that blocks ADH binding Tolvaptan = unrelated V2 antagonist |
|
|
Term
Name an oxytocin agonist and what it is used for |
|
Definition
Carbetocin used to induce/augment labour and treat post-partum haemorrhage |
|
|
Term
Name an oxytocin antagonist and what it is used for |
|
Definition
Atosiban and barusiban reduce myometrial contractions and therefore treat preterm labour |
|
|
Term
Where would you find the adrenal glands? |
|
Definition
|
|
Term
Describe the arterial blood supply of the adrenal glands: |
|
Definition
RICH the superior, middle and inferior suprarenal artery |
|
|
Term
Describe how blood returns to the systematic circulation |
|
Definition
via a single suprarenal vein |
|
|
Term
Where does the single suprarenal vein drain on the left? |
|
Definition
|
|
Term
Where does the single suprarenal vein drain on the right? |
|
Definition
directly into the inferior vena cava |
|
|
Term
Describe the blood flow of the adrenal glands |
|
Definition
1. enters via the outer regions (cortex) 2. drain through the cortex into the venules 3. this flows through the innermost region (the medulla) |
|
|
Term
What is the adrenal medulla derived from? |
|
Definition
ectodermal cells of the neural crest |
|
|
Term
Why can the medulla be considered part of the sympathetic division of the autonomic nervous system? |
|
Definition
the cells of the medulla are modified sympathetic post ganglionic fibres |
|
|
Term
What is the adrenal cortex derived from? |
|
Definition
a different embryonic cell type – the mesoderm and is specialised for secretion of a number of steroid hormones |
|
|
Term
In the foetus, what does the medulla secrete? |
|
Definition
catecholamines in response to hypoxic stress and immediately after delivery in response to cold stress |
|
|
Term
How does the adrenal gland differ in a foetus than in an adult? |
|
Definition
1. the adrenal gland is much larger in relation to the foetal body size than it is in adult life 2. The foetal adrenal gland consists of three (rather than two layers) |
|
|
Term
How is a foetal adrenal gland organised? |
|
Definition
There is a small medullary region, a small zoned cortex – called the “definitive” cortex which is like that in the adult and a third, large zone known as the foetal zone. |
|
|
Term
In the foetus, what is the role of the definitive cortex? |
|
Definition
converts progesterone to cortisol especially during the last trimester of pregnancy |
|
|
Term
How does the adrenal gland change after birth? |
|
Definition
the foetal zone regresses rapidly and the definitive cortex and medulla enlarge to take on the structure and secretory roles of the adult gland. |
|
|
Term
What is the role of the foetal zone? |
|
Definition
produces the precursor molecules required for placental synthesis of oestrogens and its large size reflects the high levels of these steroids during gestation. |
|
|
Term
What is cortisol important in? |
|
Definition
- lung and liver maturation - production of surfactant (lung inflation) - triggering role in parturition |
|
|
Term
In an adult gland, what are the zones of the cortex? |
|
Definition
Zona glomerulosa Zona fasciculata Zona reticularis |
|
|
Term
Describe the zona glomerulosa and its role |
|
Definition
outermost zone which secrete (mineralocorticoid) steroids (eg aldosterone) that regulate mineral metabolism |
|
|
Term
How can the role of the zona glomerulosa be remembered? |
|
Definition
kidneys play an important role in mineral metabolism glomerulus zona GLOMERULosa |
|
|
Term
Describe the zona fasculata and its role |
|
Definition
middle zone which secretes glucocorticoid steroids that affect the metabolism of carbohydrates and to a less extent, fats and proteins |
|
|
Term
Describe the zona reticularis and its role |
|
Definition
innermost zone that is not fully developed until 6-7 years secretes sex steroids |
|
|
Term
What does the adult medulla secrete? |
|
Definition
catecholamines: - adrenaline (epinephrine) - noradrenaline (norepinephrine) - some dopamine |
|
|
Term
Name some adreno-corticosteroids and what they are derived from |
|
Definition
derived from cholesterol - aldosterone - cortisol - sex steroids |
|
|
Term
What does aldosterone target? |
|
Definition
cells in the collecting duct and distal tubule of the kidney |
|
|
Term
What does aldosterone regulate? |
|
Definition
electrolyte balance and long term regulation of blood volume and pressure |
|
|
Term
What are the effects of aldosterone? |
|
Definition
- increase na reabsorption (and water) from kidney tubule - increase k secretion - increase h secretion |
|
|
Term
Therefore, what is the effect of aldosterone on the urine? |
|
Definition
more concentrated and acidic |
|
|
Term
What does cortisol target? |
|
Definition
many tissues: adipose, muscle and liver |
|
|
Term
What does cortisol regulate? |
|
Definition
metabolism of proteins, carbohydrates and fats |
|
|
Term
What are the effects of cortisol? |
|
Definition
- opposes the effects of insulin - conversion of protein to glycogen (especially in muscle cells) - increases amino acid supply to the liver for gluconeogenesis - immunosuppressant, anti-inflammatory and anti-allergic |
|
|
Term
How is aldosterone secretion controlled? |
|
Definition
- levels of potassium acting directly on the adrenal cortex - changes in plasma volume which is exerted via the renin-angiotensin system |
|
|
Term
Describe the events that follow increased potassium levels |
|
Definition
1. increased plasma K+ 2. release of aldosterone from the cortex stimulated 3. excretion of k+ from the kidney 4. reduced plasma k+ = reduced secretion of aldosterone |
|
|
Term
Describe the events that follow decreased blood volume/perfusion pressure |
|
Definition
1. renin released from the juxtoglomerular apparatus 2. renin converts angiotensinogen to Angiotensin I 3. Angiotensin I converted to Angiotensin II in lungs |
|
|
Term
What does Angiotensin II do? |
|
Definition
Angiotensin II is a potent vasoconstrictor (increase pressure) and releases aldosterone to increase Na+ reabsorption to help increase plasma volume |
|
|
Term
How is cortisol secretion controlled? |
|
Definition
stress ACTH is released from the AP gland and stimulates the release of cortisol controlled by negative feedback inhibiting ACTH secretion |
|
|
Term
What disorders are caused by corticosteroid secretion? |
|
Definition
Cushings syndrome Addisons disease Hyperaldosteronism |
|
|
Term
What are the causes of Cushings syndrome? |
|
Definition
- overproduction of cortisol - ACTH secreting tumour of the pituitary gland/adrenal gland - long term use of glucocorticoids used to treat inflammatory conditions |
|
|
Term
What are the physiological effects of Cushings syndrome? |
|
Definition
- truncal obesity - hyperglycaemia - redistribution of body fat - increased proteolysis = muscle wasting in proximal limbs - enhances actions of catecholamines = hypertension |
|
|
Term
What are the causes of Addisons disease? |
|
Definition
- failure of the adrenal cortex to secrete both cortisol and aldosterone - autoimmune disorder |
|
|
Term
What are the physiological effects of Addisons disease? |
|
Definition
- hypoglycaemia, loss of appetite and muscle weakness - increased ACTH and CRH (due to loss of negative feedback) = hyperpigmentation |
|
|
Term
What are the causes of Hyperaldosteronism? |
|
Definition
- hyperplasia of cells in the zona glomerulosa (Conn's syndrome) - aldosterone secreting tumours |
|
|
Term
What are the physiological effects of Hyperaldosteronism? |
|
Definition
- hypokalaemia - sodium retention - alkolosis - hypertension - low renin |
|
|
Term
Explain how mineralocorticoid selectivity is enzyme based |
|
Definition
- cortisol and aldosterone bind with equal affinity to receptor (MR) - cortisol has higher plasma concentration - MR enzyme (11βHSD2) converts intracellular cortisol to cortisone which has low affinity for the MR and generates high levels of NADH - Generated NADH maintains cortisol–MR complexes in an inactive state and permits aldosterone to selectively activate the receptor, despite higher intracellular cortisol levels. |
|
|
Term
How can inhibition of 11βHSD2 lead to hypertension? |
|
Definition
Inhibitors of 11βHSD2 such as glycyrrhetinic acid, the active compound of licorice allows cortisol activation of MR, resulting in hypertension. |
|
|
Term
What happens once a mineralocorticoid receptor complex is made? |
|
Definition
translocates to nucleus and starts transcription |
|
|
Term
What are the adrenals innervated by? |
|
Definition
the thoracic sympathetic sypathetic chain |
|
|
Term
Describe the innervation of the adrenal medulla |
|
Definition
The sympathetic preganglionic fibres innervate (acetylcholine is the neurotransmitter) and stimulate chromaffin cells (which are essentially a specialised forms of sympathetic postganglionic fibre) in the medulla to secrete catecholamines. |
|
|
Term
List the catecholamines released from the medulla |
|
Definition
Epinephrine (80%) Norapinephrine (20%) Dopamine (<1%
ALL DERIVED FROM THE AA TYROSINE |
|
|
Term
|
Definition
Tyrosine is hydroxylated to dihydroxyphenylalanine (DOPA) which is then decarboxylated to form Dopamine |
|
|
Term
How is norapinephrine formed? |
|
Definition
Dopamine is further hydroxylated to form norepinephrine (noradrenaline) |
|
|
Term
How is epinephrine formed? |
|
Definition
norepinephrine (noradrenaline) with the addition of a methyl group forms epinephrine (adrenaline). |
|
|
Term
How are catecholamines released? |
|
Definition
The chromaffin cells contain secretory granules containing one or other catecholamine and a variety of opioid peptides (enkephalins). Release into the blood stream is via exocytosis in response to acetylcholine release from sympathetic pre-ganglionic fibres. |
|
|
Term
What receptors do medullary catecholamines bind to? |
|
Definition
GPCRs with secondary messenger systems alpha and beta |
|
|
Term
Which shows higher affinity for norepinephrine and which epinephrine? |
|
Definition
alpha = norepinephrine beta = epinephrine |
|
|
Term
What causes overproduction of adrenal catecholamines? |
|
Definition
chromaffin tumour (chromaffinoma) known as phaeochromocytoma |
|
|
Term
What does overproduction of adrenal catecholamines lead to? |
|
Definition
Leads to severe hypertension, hyperglycaemia |
|
|
Term
Name the 4 bones that makes up the pelvis |
|
Definition
Left innominate Right innominate Sacrum: 5 fused vertebrae Coccyx: 4 fused vertebrae |
|
|
Term
What is each innominate made up of? |
|
Definition
|
|
Term
What are the pelvic divisions and what separates them? |
|
Definition
Greater pelvis and lesser pelvis, seperated by the pelvic brim/inlet |
|
|
Term
Name and describe the 3 parts of the unterine/fallopian tubes |
|
Definition
Laterally (infundibulum) Ampulla (usual fertilisation site) Isthmus (narrow part) |
|
|
Term
What are the 3 layers of the uterus? |
|
Definition
Perimetrium Myometrium Endometrium (out to in) |
|
|
Term
What are uterine fibroids? |
|
Definition
non cancerous uterine growths (variable size and location) |
|
|
Term
When is the uterus usually damaged? and why |
|
Definition
When pregnant. Uterus enlarges and rises out of pelvis can obstruct the inferior vena cava |
|
|
Term
How does a mother adapt to prevent injury? |
|
Definition
increased blood volume to protect from hypovolemic shock uterus is thick and muscular and distributes force of trauma uniformally to fetus |
|
|
Term
What are the male glands and what do they produce? |
|
Definition
seminal vescile -> seminal fluid prostate -> produces prostatic fluid bulbaretural -> produces pre-ejaculate |
|
|
Term
What is the spermatic cord and what does it include? |
|
Definition
Attaches scrotum to the body -ductus deferens - blood vessels -nerves (enclosed in a muscular sheath) |
|
|
Term
Describe the ejaculatory pathway |
|
Definition
testes -> ductus deferens (and seminal vesicles) -> ejaculatory ducts -> prostatic/membranous urethra -> penis
TRAV picks up DANA AND SAM and EATS DOMINOS, they PULL UP at the MEET UP and PARTY |
|
|
Term
Describe the composition of semen |
|
Definition
Sperm (2-5%) Semen (65-75%) Prostatic fluid (25-30%) |
|
|
Term
|
Definition
Used to cut off bad prostate Resectoscope enters urethra and electrical currents heats the hoop to cut parts off. Water is flushed through to remove pieces. |
|
|
Term
How is the uterus supported? |
|
Definition
via the broad ligament: a double layer of peritoneum draped over uterus and uterine tubes |
|
|
Term
What does the broad ligament contain? |
|
Definition
1) round ligament (uterus to labia majorum) 2) ovarian ligament (ovary to uterus) 3) suspensory ligament (ovary to laeral pelvic wall, contains ovarian vessels) |
|
|
Term
|
Definition
weakening of pelvic floor muscles or damage during childbirth |
|
|
Term
List the erectile bodies of the penis |
|
Definition
- corpus cavernosa (x2 dorsally) - corpus spongium (ventrally) |
|
|
Term
What are the 3 layers of the uterus (out to in)? |
|
Definition
perimetrium myometrium endometrium |
|
|
Term
What are the 4 parts of the uterus? |
|
Definition
|
|
Term
Describe the anatomy of the uterine/fallopian tubes |
|
Definition
1. run from near the ovaries to the uterus 2. on the lateral part is the infundibulum (funnel shaped with fimbrae) 3. the ampulla 4. the isthmus |
|
|
Term
What is the usual site for fertilisation? |
|
Definition
|
|
Term
In males, what is the vesico-rectal pouch? |
|
Definition
formed from the peritoneum (thin serous membrane) drapes over both the bladder and rectum |
|
|
Term
What are the four parts of the male urethra? |
|
Definition
1. pre-prostatic urethra 2. prostatic urethra 3. membranous urethra 4. spongy urethra (or penile urethra) |
|
|
Term
What is the male reproductive system made up of? |
|
Definition
testes ductus (vas deferens) seminal vesicles ejaculatory ducts prostate penis |
|
|
Term
What are the testes and what do they produce? |
|
Definition
the male gonads and the produce germ cells and the hormone testosterone |
|
|
Term
What is each testes suspended within? |
|
Definition
the scrotal sac by the spermatic cord which contains the ductus (vas) deferens, blood vessels and nerves |
|
|
Term
Describe the outer layer of each testis |
|
Definition
Each testis has a tough fibrous outer layer known as the tunica vaginalis |
|
|
Term
What does the tunica vaginalis enclose? |
|
Definition
both the seminiferous tubules and the epididymis |
|
|
Term
What happens once sperm have gained full maturity within the epididymis? |
|
Definition
they enter the ductus (vas) deferens |
|
|
Term
What is the ductus (vas) deferens? |
|
Definition
a muscular cord with a thin lumen extending from te epididymis at the inferior pole of the testis |
|
|
Term
How does the ductus deferens enter the body? |
|
Definition
1. ascend within the spermatic cord 2. enters through the inguinal canal 3. |
|
|
Term
Describe the route of the ductus deferens once it pierced the anterior abdominal wall |
|
Definition
1. travels across the pelvic brim 2. runs along the lateral wall of the pelvis to join the seminal vesicle behind the bladder 3. this forms the ejaculatory duct |
|
|
Term
Does the ductus deferens run over or under the uterior? |
|
Definition
|
|
Term
What are the ejaculatory ducts formed by? |
|
Definition
the union of the ductus deferens and the seminal vesicles at the posterior bladder neck |
|
|
Term
Where do the ejaculatory ducts run and empty? |
|
Definition
they run through the posterior aspect of the prostate they empty its contents into the prostatic part of the urethra |
|
|
Term
What is the function of the seminal vesicles? |
|
Definition
|
|
Term
What is the function of seminal fluid? |
|
Definition
1. rich in sugars (especially fructose), which feeds the sperm. 2. The fluid also has clotting properties that make the semen sticky. This ensures that the semen clings inside the vagina long enough for the sperm to travel to the egg. |
|
|
Term
Where is the prostate gland? |
|
Definition
sits inferiorly to the bladder with the prostatic urethra descending through it |
|
|
Term
What do the prostatic ducts open into? |
|
Definition
prostatic sinuses, either side of the seminal colliculus, which contain the openings of the ejaculatory ducts |
|
|
Term
What is the function of the prostate? |
|
Definition
The prostate secretes a milky substance that makes up around 20 to 30 percent of semen. It also has muscles that help to expel the semen during ejaculation. |
|
|
Term
What would be the consequence of an enlarged prostate? |
|
Definition
a doctor will schedule a manual rectal prostate exam if one of these disorders is suspected. The doctor will place his or her finger into your rectum and examine the prostate for unusual swelling. |
|
|
Term
What procedure could reduce the size of a prostate? |
|
Definition
|
|
Term
What happens to the erectile bodies during sexual arousal? |
|
Definition
erectile tissues dilate and fill with blood causing the penis to become erect |
|
|
Term
What does the female pelvis include? |
|
Definition
the reproductive organs: vagina, uterus, uterine tubes and ovaries |
|
|
Term
Describe the positioning of the vagina, uterus, bladder and rectum |
|
Definition
the vagina and uterus are positioned between the bladder and rectum |
|
|
Term
Describe the pouches in the female |
|
Definition
a thin serous sheet, the peritoneum, drapes down from the abdomen and covers these organs forming two pouches: vesico-uterine and utero-rectal |
|
|
Term
|
Definition
a musculo-membranous channel that extends from the vestibule, a cleft between the labia minora and the cervix |
|
|
Term
How is the vagina normally? |
|
Definition
collapsed both the anterior and posterior walls are in contact except ath the superior limit of the vaginal canal where the cervix holds the walls apart |
|
|
Term
|
Definition
a narrowing of the uterus that extends into the superior limit of the vagina, creating the fornix, a gutter around the protruding cervix. |
|
|
Term
What is the posterior fornix? |
|
Definition
the deepest of the fornices and is in close contact with the utero-rectal pouch |
|
|
Term
How can the uterus be divided? |
|
Definition
into a fundus, body and cervix |
|
|
Term
What are the uterine walls composed of? |
|
Definition
three layers (deep to superficial): endometrium, myometrium and perimetrium |
|
|
Term
What does the uterus house? |
|
Definition
the development of the embryo and foetus and provides muscular force during childbirth |
|
|
Term
What orientation does the uterus assume? |
|
Definition
anterverted - anteflexed so that the body lies over the superior aspect of the bladder |
|
|
Term
|
Definition
a surgical operation to remove all or part of the womb. |
|
|
Term
Via which two surgical procedures can a womb be removed? |
|
Definition
1. stomach sruger 2. vaginally |
|
|
Term
|
Definition
almond shaped structures that are responsible for the production and release of the female germ cells, the ova. |
|
|
Term
How are ovaries suspended? |
|
Definition
Each ovary sits in the lateral part of the pelvis and is suspended within the broad ligament by the suspensory and ovarian ligaments |
|
|
Term
Describe the blood supply of the pelvis |
|
Definition
by aorta which splits into external and internal iliac arteries |
|
|
Term
Where are the female hormones secreted from? |
|
Definition
Hypothalamus Pituitary gland Ovaries |
|
|
Term
What is the first stage of the menstrual cycle? |
|
Definition
mentruation - shedding of the uterine lining |
|
|
Term
How many eggs are released per cycle? |
|
Definition
1 egg at around the 14th day |
|
|
Term
|
Definition
the release of the egg from the ovaries |
|
|
Term
|
Definition
the periodic process in which immature ovarian follicles degenerate and are subsequently re-absorbed during the follicular phase of the menstrual cycle. |
|
|
Term
What is found within the ovaries? |
|
Definition
follicles that are embedded within the connective tissue |
|
|
Term
What is a primordial follicle? |
|
Definition
- contains an oocyte in the middle - contains a layer of epithelial cells around the outside known as follicle cells (which develop into granulosa cells) |
|
|
Term
|
Definition
a cell in an ovary which may undergo meiotic division to form an ovum. |
|
|
Term
When does an epithelial layer become a granulosa layer? |
|
Definition
when there is more than one epithelial layer |
|
|
Term
What does a primordial cell become? |
|
Definition
a theca cell (more mature and developed) |
|
|
Term
List the stages of the ovarian cycle |
|
Definition
1. follicular phase (first 14 days) 2. luteal phase (last 14 days) |
|
|
Term
Describe the events of the follicular phase |
|
Definition
1. begins with menstruation 2. ends with ovulation (release of egg into uterine tubes) |
|
|
Term
Most follicles within the ovary are in the ____ phase |
|
Definition
|
|
Term
What happens to the small remaining fraction of follicles? |
|
Definition
they begin to develop independently of each other |
|
|
Term
What do they develop into? |
|
Definition
A preantral follicle -granulosa cells surrounded by a layer of theca cells |
|
|
Term
What does a preantral follicle develop into and how does this differ? |
|
Definition
an early antral follicle this contains a fluid filled cavity (antrum) |
|
|
Term
What does an early antral follicle develop into and how does this differ? |
|
Definition
the dominant follicle (the later antral follicle) - the antrum has grown much bigger and is surrounding the oocyte |
|
|
Term
Describe ovulation explicitly |
|
Definition
The dominant follicle (at around 2cm diameter) bursts and releases the egg into the uterine tube this is the beginning of the luteal phase |
|
|
Term
What structure is left in the ovary after ovulation? |
|
Definition
|
|
Term
What causes the dominant follicle to burst? |
|
Definition
- leutinising hormone (LH) increases - releases proteolytic enzymes which ruptures the wall |
|
|
Term
What is the fate of the oocyte if there is no fertillisation? |
|
Definition
the corpus luteum structure lasts for about 10 days and causes the secretion of estrogen and progresterone |
|
|
Term
What does the corpus luteum become if no fertillisation? |
|
Definition
corpus albicans which causes a decrease om the secretion of estrogen and progresterone and hence stimulation of menstruation |
|
|
Term
What is the fate of the corpus luteum if there is fertillisation? |
|
Definition
The corpus luteum will persist as astructure and continue to stimulate the secretion of estrogen and progresterone |
|
|
Term
What are the phases of the uterine cycle? |
|
Definition
Menstrual phase (day 1-5) Proliferative phase (day 5-14) Secretory phase (day 14-28) |
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Term
What happens in the menstrual phase of the uterine cycle? |
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Definition
the shedding of the uterine lining endometrial thickness decreases caused by reduced levels of estrogen and progresterone |
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Term
What happens in the proliferative phase of the uterine cycle? |
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Definition
uterus renews itself in preparation for a potential pregnancy |
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Term
What causes the proliferative phase of the uterine cycle? |
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Definition
promoted by increase in estrogen caused by the development of the dominant follicle - causes the development of blood vessels and nutrients in the uterus |
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Term
What happens in the secretory phase? |
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Definition
uterus is transformed in transformed into favourable place for implantation and potentially housing an embryo |
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Term
Name the 4 important hormones involed in the female reproductive cycle |
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Definition
LH FSH estrogen progesterone |
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Term
Describe the changes in oestrogen levels over the female cycle |
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Definition
starts to peak just before ovulation then declines until just after and then raises again then drops (then starts to peak...) |
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Term
Describe the changes in progesterone levels over the female cycle |
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Definition
stays very low until the secretory phase where it peaks mid phase then declines again |
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Term
Describe the changes in LH and FSH levels over the female cycle |
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Definition
huge surge at period of ovulation (LH more) |
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Term
What events happen early to mid follicular phase? |
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Definition
1. FSH binds to receptors on granulosa cells (which causes growth and proliferation of the follicle) 2. Outer layer theca cells develop and gain more LH receptors 3. Dominant follicle secretes andorgens (specifically oestrogen) |
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Term
Describe the FSH feedback system |
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Definition
FSH binds to granulosa cells which release inhibin. Inhibin reduces FSH levels so that ovulation does not occur before the follicle is ready |
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Term
Describe the oestrogen feedback system |
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Definition
Affects the hypothalamus and anterior pituitary to control the levels of LH and FSH |
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Term
How is FSH released and what effect does it have? |
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Definition
1. Hypothalamus secrets GnRH 2. Anterior Pituitary secretes FSH 3. FSH binds to receptors on granulosa cells (which causes growth and proliferation of the follicle) 4. Controlled by negative feedback system of inhibin with the anterior pituitary |
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Term
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Definition
1. Hypothalamus secrets GnRH 2. Anterior Pituitary secretes LH 3. Acts on theca cells to cause oestrogen secretion 4. controlled by negative feedback with the anterior pituitary and hypothalamus to maintain oestrogen and LH levels |
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Term
Describe the hormonal changes in the late follicular phase |
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Definition
1. oestrogen acts on hypothalamus and AP (changes from negative feedback to positive feedback) 2. increases LH (mainly) and FSH levels |
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Term
What does oestrogen stimulate? |
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Definition
stimulates granulosa cells to express more LH receptors |
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Term
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Definition
a few hours before ovulation |
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Term
What secretes more oestrogen, the dominant follicle or corpus luteum? |
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Definition
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Term
Why does LH hormone decrease? |
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Definition
there is far less oestrogen and therefore no longer a stimulus for LH secretion |
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Term
What does the corpus luteum secrete? |
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Definition
1. inhibin (reduces FSH levels) 2. oestrogen (not much) 3. progesterone (uterus and breasts) |
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Term
How does preogesterone affect the uterus? |
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Definition
1. secretory phase changes 2. stops contractile activity (allows it to be a favourable place for implantation) |
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Term
How does preogesterone affect the breasts? |
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Definition
1. growth of glandular tissue 2. supression of lactation |
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Term
Describe the negative feedback system of progresterone |
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Definition
affects AP and hypothalamus limits the growth of a new follicle as we don't known if the just released oocyte will be fertillised or not |
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Term
How does the uterus change during mensturation? |
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Definition
- endometrium thickens - follicles secrete oestrogen - increased number of glands and blood vessels |
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Term
How thick is the endometrium during ovulation? |
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Definition
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Term
How does the uterus change during secretory phase? |
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Definition
- increased cellular proliferation - secretion of hormones and cytokines - increased lipids and glycogens (nutrients) - increased blood supply - corpus luteum secretes P and Oe |
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Term
How thick is the endometrium during the secretory phase? |
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Definition
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Term
What causes menstruation? |
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Definition
decreased levels of oestrogen and progesterone |
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Term
Describe the events of menstruation |
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Definition
1. vasodilation (prostaglandin 2 alpha) 2. necrotic outer layers of the endometrium separate from the uterus 3. seperated tissue and blood initiate contractions 4. contents expelled |
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Term
The surge of LH mid ovarian cycle triggers... |
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Definition
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Term
What events occur during the secretory phase, overall? |
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Definition
- fertillised ovum implants - progesterone levels are high - corpus luteum is formed - endometrial glands enlarge |
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Term
How long does the sperm have to meet the ovum, post ovulation? |
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Definition
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Term
How long can the sperm live within the uterine tube for? |
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Definition
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Term
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Definition
1. sperm and ovum meet in ampulla 2. sperm binds to receptors on membrane 3. oocyte will transport sperm into cyotplasm 4. sperm disintergrates and releases chromosones into cytoplasm 5. chromosomes combine 6. zygote formed |
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Term
What happens to the zygote? |
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Definition
1. undergoes mitotic division 2. becomes a blastomere and then a morula |
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Term
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Definition
3-4 days post fertillisation contains about 16 blastomeres |
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Term
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Definition
4-5 days post fertillisation contains a fluid filled cavity this moved down the uterus and implants 6 days post fertilisation |
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Term
When is the term embryo used? |
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Definition
between 2 and 7-8 weeks post fertillisation |
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Term
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Definition
trophoblastic cells invading the endometrium |
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Term
How long is the average pregnancy? |
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Definition
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Term
How does the embryo receives its nutrients in the early stages of pregnancy? |
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Definition
the endometrium (later on it receives it from the placenta) |
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Term
How can a baby and a mother have different blood types? |
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Definition
Their blood never mixes. The maternal vessels run very close to the placenta and the fetal blood vessels run into the placenta. |
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Term
Describe the changes in hCG secretion |
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Definition
- begins at implantation and increases for the first 3 months of pregnancy - similar structure to LH |
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Term
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Definition
- produced by trophoblast cells - autonomous (not hypothalamus or AP) |
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Term
Describe the changes in oestroegn and progesterone secretion |
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Definition
continue rising until parturition |
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Term
Describe Human Placental Lactogen |
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Definition
polypeptide hormone secreted in increasing concentrations during pregnancy |
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Term
What are the effects of Human Placental Lactogen |
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Definition
1. stimulates lipolysis in the mother 2. inhibits glucose uptake in the mother 3. promotes the growth and differentiation of the breasts |
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Term
What forms does oestrogen come in in pregnancy and where are they produced? |
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Definition
- oestradiol produced by the corpus luteum and the placenta - oestriol produced by the foetus and the placenta |
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Term
What are the effects of oestrogen in early pregnancy? |
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Definition
1. growth/strength of the myometrium 2. increases contractile proteins to accomodate the growing fetus in the female |
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Term
What are the effects of oestrogen in mid pregnancy? |
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Definition
to increase the blood flow to the placenta to help exchange nutrients/waste products |
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Term
What are the effects of oestrogen in late pregnancy? |
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Definition
1. part of the multi-hormonal increase 2. preparation of breasts for lactation 3. increases sensitivity of the uterus to contractile proteins (for labour) |
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Term
What is the role of progesterone during pregnancy? |
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Definition
- inhibits uterine smooth muscle contractility (oestrogen is the antagonist) - keep uterus quiescent during pregnancy - inhibits production of contractile proteins so labour doesn't occur early |
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Term
How does progesterone affect immunity? |
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Definition
inhibits T cell mediated responses (as foetus is 'foreign' |
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Term
When is prolactin released? |
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Definition
after birth to stimulate lactation spiked |
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Term
Name the 4 parts of the male reproductive system |
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Definition
Testes External genitalia reporductive tract accessory glands |
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Term
Name the male external genitalia |
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Definition
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Term
Name the male accessory glands |
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Definition
seminal vesicles prostate gland bulbourethral gland |
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Term
What is the role of the penis? |
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Definition
Penetrates vagina and deposits sperm |
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Term
What does the penis undergo during sexual arousal? |
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Definition
Erection: - Blood flow to penis increases - Engorges erectile tissue - Penis swells and elongates |
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Term
What is the role of the scrotum and where is it? |
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Definition
Suspended beneath penis Houses testes Sperm cannot develop at body temperature Allows a cooler environment for sperm development |
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Term
How many compartments do the testes have? |
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Definition
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Term
What are the testes encapsulated in? |
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Definition
a layer of fibrous connective tissue |
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Term
What is found in each compartment? |
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Definition
highly coiled thin tubules (seminiferous tubules) this is where sperm is produced |
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Term
What cells are there in the testes? |
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Definition
Leydig cells (secrete hormones eg testosterone) |
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Term
What cells make up the seminiferous tubules? |
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Definition
there is an outer layer of smooth muscle then sertoli cells then lumen |
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Term
Where would you find the more mature sperm? |
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Definition
the lumen of the tubules this is filled with fluid |
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Term
What is the role of the smooth muscle cell layer? |
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Definition
exhibit peristaltic contractions will help propel sperm and fluid along this highly coiled tubes |
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Term
Where are tight junctions found and why? |
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Definition
between the epithelial (sertoli) cells they form the blood testes barrier |
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Term
What does the blood testes barrier separate? |
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Definition
this isolates the lumenal fluid from the spermatagoa as sperm only contains 23 chromosomes the body would attack it if the barrier didn;t protect it |
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Term
What are the functions of Sertoli cells? |
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Definition
- support sperm development - secrete several important things - target cells |
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Term
What do Sertoli cells secrete? |
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Definition
- luminal fluid in which sperm develop - androgen-binding protein - inhibin - Mullerian inhibiting substance (MIS) |
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Term
What is the significance of inhibin secretion? |
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Definition
hormone of negative feedback loop for FSH |
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Term
What are Sertoli cells targets for? |
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Definition
testosterone and FSH they secrete chemicals that stimulate spermatogenesis |
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Term
Describe the reproductive tract |
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Definition
1. sperm develops in the seminiferous tubules 2. Rete testis 3. Efferent ductules (exits testis) 4. Epidiymis (larger tube with thicker walls) 5. Vas deferens (into pelvic cavity) 6. two vas deferens near the seminal vesicles 7. ejaculatory duct (converge) 8. passes through the prostate gland 8. urethra (via bulbourethral glands) |
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Term
What do the seminal vesicles secrete? |
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Definition
alkaline fluid with fructose, enzymes and PGs |
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Term
What does the prostate gland secrete? |
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Definition
secrete citrate (energy) and enzymes and prostate specific antigen (PSA) |
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Term
What does the bulbourethral gland secrete? |
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Definition
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Term
What can prostate specific antigen be monitored for? |
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Definition
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Term
Which male sex hormones are released from the AP and how? |
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Definition
1. hypothalamus 2. GnRH secretion 3. Anterior pituitary 4. FSH and LH secretion |
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Term
Where does FSH have an affect? |
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Definition
Sertoli cells. Causes: - inhibin secretion - spermatogenesis |
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Term
How are FSH levels controlled? |
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Definition
Inhibin controls via negative feedback to the AP |
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Term
Where does LH have an affect? |
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Definition
Leydig cells. Causes testosterone secretion which affects Sertoli cells |
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Term
How are LH levels controlled? |
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Definition
Negative feedback for AP and hypothalamus |
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Term
What are the effects that androgens (testosterone) has on various tissue targets? |
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Definition
1. maintenance of accessory reproductive organs 2. maintenance of secondary sex characteristic 3. increase sex drive 4. increased protein synthesis in skeletal muscle 5. increased bone growth in adolescence |
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Term
What are the 3 parts of the sperm? |
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Definition
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Term
What does the head of the sperm contain? |
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Definition
Chromosomes Acrosome (which contains enzymes necessary for fertilisation) |
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Term
What does the midpiece contain? |
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Definition
mitochondria (produces ATP) |
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Term
What is the role of the tail for the sperm? |
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Definition
whip like movements propel the sperm |
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Term
Where does sperm develop? |
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Definition
between the two epithelial sertoli cells (from the basement membrane down to the lumen)
there is a tight junction between the two cells (blood testis barrier) |
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Term
Describe the start of spermatogenesis |
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Definition
at the basement membrane in the seminiferous tubules from undifferentiated germ cells (spermatogenia) |
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Term
What happens to the spermatogenia |
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Definition
they migrate towards the lumen through the sertoli cells mitosis (splits) one goes back to the germ cell pool the other undergoes another meiosis then meiosis again then becomes spermatoza |
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Term
What happens to the spermatoza |
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Definition
they remain immotile for 20 days in luminal fluid they move down epididymas and persistalsis moves them down vas deferens when aroused |
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Term
What is male reproduction mainly under the control of? |
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Definition
GnRH, Testosterone, FSH, LH and (negative feedback) inhibins. |
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Term
What are the different types of oral contraceptive pills? |
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Definition
Combined pill (Oestrogens and progestins) or Mini pill (progestin only) |
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Term
What are the main effects of the oral contraceptive pill? |
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Definition
prevent ovulation (production of the egg) |
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Term
What are the secondary effects of the oral contraceptive pill? |
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Definition
discourage fertilisation eg: implantation |
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Term
Name the synthetic oestrogens |
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Definition
Ethinylestradiol and mestranol (similar potency) |
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Term
Name the synthetic progestins |
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Definition
Northisterone, levonorgestrel – first generation Desogestrel, gestodene- newer agents
Different potencies |
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Term
What causes the side effects of progestins? |
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Definition
Northisterone -> adrogenic (increase levels of oestrogens and stimulate male sexual characteristics)
Gestodene and desogestrel -> antiandrogenic (lower levels of oestrogen) and stimulate SHBG (produced when pregnant therefore stops pregnant) |
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Term
What is the most popular (and cheapest) type of combined oral contraceptive? |
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Definition
monophasic identical 21 pills contain oestrogen plus progesterone |
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Term
What are the more complex bi/triphasic combined pills like? |
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Definition
Designed to mimic cycle more closely Both oestrogen and progestin dose varied once or twice Often need higher oestrogen dose to inhibit ovulation Progestin overall intake reduced – less side effects |
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Term
What are the side effects of the combined pill? |
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Definition
Breakthrough bleeding Weight gain Effect sexuality Depression |
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Term
Describe the mechanism of the combined pill? |
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Definition
Based on the fact that ovulation is suppressed in pregnancy Progesterone increases (when pregnant) S |
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Term
Which hormones are suppressed by negative feedback at hypothalamus and pituitary? |
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Definition
Suppressed secretion of FSH and LH Low FSH suppressed by oestrogen Low LH, Progestin effects LH surge |
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Term
What are the specific effects of the combined pill? |
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Definition
Cervical mucus thickens, viscous and scanty Impairs motility of uterus and oviduct Endometrial changes not conducive to implantation Decreased production of glycogen- decreased energy for blastocyst to survive in uterus |
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Term
How does the mini pill differ? |
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Definition
progestin only everyday (no 7 day break) |
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Term
Who is the mini pill recommended for? |
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Definition
Breast-feeding mothers Women who cannot take oestrogens Diabetics-though younger ones may take the combined pill Older women Heavy smokers Anyone who wants to take a break from the combined pill |
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Term
What are the side effects of the mini pill? |
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Definition
irregular bleeding, amenorrhoea, ectopic pregnancy unpredictable bleeding mastalgia weight gain but less than combined small risk of breast cancer but less than combined |
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Term
What are the benefits of oral contraceptives? |
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Definition
Can reduce period pains Periods shorter and lighter - because of this, you are less likely to become anaemic Acne, the Pill should improve it Delay menstruation Can decrease chances of getting certain cancers (though it increases the risk of others) |
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Term
What are the risks of oral contraceptives? |
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Definition
DVT, clotting Heart attacks, strokes More common if smoke, overweight, diabetic, high blood pressure, high cholesterol |
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Term
What are the other hormone based contraceptions? |
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Definition
Injectable progestin (Depo Provera) Subcutaneous implants (Norplant) Hormone impregnated IUD (Mirena) |
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Term
Describe Injectable progestin (Depo Provera) |
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Definition
Intramuscular injection of medroxy-progesterone acetate (DMPA) prevents surge LH |
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Term
Describe Subcutaneous implants (Norplant) |
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Definition
Progestin e.g. levonorgestral released from implanted silicone capsules/tubes |
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Term
Describe Hormone impregnated IUD (Mirena) |
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Definition
IUD – made from inert plastic (not copper coil) Progestin impregnated Prevent sperm reaching fallopian tube |
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Term
Describe post-sexual intercourse preparations |
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Definition
Morning after pills Effective if first dose taken within 24-72 hours. Taking first dose ASAP increases efficacy. Lessens the later you leave it. |
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Term
What does morning after pill do? |
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Definition
Delays ovulation Interfere with transport and implantation Interferes with endometrial development Failure rate 10% Nausea |
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Term
Describe the abortion pill |
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Definition
Anti progesterone (abortion pill) For pregnancies up to 63 days (9 weeks) Binds to progesterone receptors Gestation up to 63 days 36-48 hours after taking mifepristone – insert prostaglandins in vagina and causes uterine contractions leading to miscarriage |
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Term
What is a natural contraception method? |
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Definition
1. not having sex between day 10 and day 17 of the cycle 2. monitor temp (Temp increase by 0.4 -0.8°F between 1 and 3 days after ovulation) 3. Assessment of cervical mucus – Billings method 4. Kits predicting ovulation |
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Term
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Definition
35% female 24% male 28% unexplained 13% other |
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Term
what is inversely proportional to percent of max fertility for females? |
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Definition
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Term
What factors cause female infertility? |
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Definition
ovulatory failure impared gamete/zygote transport implantation defects developmental abnormalities of internal genitalia |
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Term
What is the favourable sperm count? |
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Definition
Count: approx. 40 million Concentration: 20 million/ml |
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Term
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Definition
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Term
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Definition
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Term
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Definition
Sperm morphology is wrong |
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Term
Define oligoasthenoteratozoospermia |
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Definition
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Term
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Definition
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Term
What can be done to help a female ovulate? |
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Definition
The use of medication to stimulate the ovaries into producing oocytes Clomiphene citrate: orally active increased FSH and LH Injectable gonadotrophins GnRH pump Bromocriptine |
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Term
Describe clomiphene citrate |
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Definition
“Selective Estrogen Receptor Modulators” (SERMs) A non-steroidal compound with close structural similarity to oestradiol |
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Term
What does clomiphene citrate act as? |
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Definition
Clomiphene is a partial agonist in the ovaries and oestrogen receptor antagonist in the hypothalamus. |
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Term
Describe the mechanism of action of clomiphene citrate |
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Definition
inhibits the negative feedback of oestrogen in turn promotes gonadotrophin release promotes release of FSH and LH stimulates ovulation |
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Term
How effective is clomiphene? |
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Definition
ovulation is induced in about 70% of cases pregnancy occurs in only 10-15% of cases |
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Term
Why does clomiphene citrate have low pregnancy rates? |
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Definition
1.anti-oestrogenic effects on cervix - makes hostile to sperm penetration - affects embryo implantation 2.can cause premature luteinisation 3.decrease in quality of ova produced |
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Term
What injectable Gonadotrophins are there? |
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Definition
Follitropin FSH Started early in cycle 8-14 days Induces production of follicles |
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Term
What injectable menotrophin are there? |
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Definition
Menotrophin HCG Induces ovulation approx 36 hours later Risk of overstimulation 90% anovulatory women ovulate Pregnancy rate 15% |
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Term
What methods of assisted contraception are there? |
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Definition
Intrauterine insemination (IUI) Artificial insemination (AI) IVF-ET: in vitro fertilisation and embryo transfer |
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Term
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Definition
Fertilisation occurs outside the body Embryo transferred afterwards Most useful where the women has absent or blocked fallopian tubes |
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