Term
|
Definition
Occurs between 2 cells of the same type, and the cells must be in extensive physical contact.
-through gap junctions
-ions, small solutes,lipid soluble materials
-usu. limited to adjacent cells of the same type |
|
|
Term
|
Definition
1) coordinate ciliary movement among epithelial cells
2) coordinate the contractions of cardiac muscle cells
3)facilitate the propagation of action potentials from one neuron to the next |
|
|
Term
|
Definition
The use of chemical messengers to transfer information from cell to cell within a single tissue
-through extracellular fluid
-most common form of extracellular communication |
|
|
Term
|
Definition
Local hormones
Ex. prostaglandins |
|
|
Term
|
Definition
| chemical messengers that are released in one tissue and transported in the bloodstream to alter the activities of specific cells in other tissues. |
|
|
Term
|
Definition
| Specific cells that have the receptors needed to bind and "read" the hormonal message |
|
|
Term
| mechanisms of action of hormones |
|
Definition
A)stimulate the synthesis of an enzyme or a structural protein not already present in the cytoplasm by activating appropriate genes in the cell nucleus
B)increase or decrease the rate of synthesis of a particular enzyme or protein by changing the rate of transcription or translation
C)turn an existing enzyme or membrane channel "on" or "off" by changing its shape or structure |
|
|
Term
| 4 mechanisms of intercellular communication |
|
Definition
| Direct, paracrine, endocrine, and synaptic |
|
|
Term
|
Definition
1)Amino acid derivatives
2)Peptide hormones
3)Lipid derivatives |
|
|
Term
| Amino acid derivatives (biogenic amines) |
|
Definition
|
|
Term
| What is the primary hormone made from tryptophan? |
|
Definition
| Melatonin, produced by the pineal gland |
|
|
Term
| 2 groups of peptide hormones |
|
Definition
1)Glycoproteins
2)short polypeptides and small proteins |
|
|
Term
| 2 classes of lipid derivatives |
|
Definition
1)Eicosanoids
2)steroid hormones |
|
|
Term
| The endocrine system includes: |
|
Definition
| All the endocrine cells and tissues of the body that produce hormones or paracrine factors with effects beyond their tissues of origin |
|
|
Term
| How long does a freely circulating hormone remain functional? |
|
Definition
| Less than one hour, or as little as 2 minutes |
|
|
Term
| Free hormones are inactivated by: |
|
Definition
1) it diffuses out of the bloodstream and binds to receptors on target cells
2) it is absorbed and broken down by cells of the liver or kidneys
3) it is broken down by enzymes in the blood or interstitial fluid |
|
|
Term
|
Definition
| Levels of particular hormone are high, receptor numbers decrease, cells become less sensitive |
|
|
Term
|
Definition
Absence of a hormone triggers increase in number of hormone receptors
Levels of particular hormone are low, cells become more sensitive |
|
|
Term
|
Definition
the functional counterparts of neural reflexes.
Can be triggered by:
-humoral stimuli (changes in the composition of the extracellular fluid)
-hormonal stimuli (the arrival or removal of a specific hormone)
-neural stimuli (the arrival of neurotransmitters at neuroglandular junctions) |
|
|
Term
| The hypothalamus provides the highest level of endocrine control. It integrates the activities of the nervous and endocrine systems in 3 ways: |
|
Definition
1) hypothalamus acts as an endocrine organ.
2) Secretes regulatory hormones which control the secretory activities of endocrine cells in the anterior lobe of the pituitary gland, which then control the activities of endocrine cells in the thyroid, adrenal cortex, and reproductive organs.
3) Contains autonomin centers that exert direct neural control over the endocrine cells of the adrenal medullae. |
|
|
Term
| Pituitary gland (hypophysis) |
|
Definition
lies within the sella turcica
connected to the hypothalamus by the infundibulum
held in position by the sellar diaphragm
has anterior and posterior lobes |
|
|
Term
| Anterior lobe of the pituitary gland |
|
Definition
3 regions:
-Pars distalis: largest and most anterior portion
-Pars tuberalis: wraps around the adjacent portion of the infundibulum
-Pars intermedia: narrow band bordering the posterior lobe |
|
|
Term
|
Definition
| a swelling near the attachment of the infundibulum |
|
|
Term
|
Definition
Involves only one hormone, endocrine cell responds to changes in extracellular fluid
Controls hormone secretion by the heart, pancreas, parathyroid gland, and digestive tract |
|
|
Term
|
Definition
Involves one or more intermediary steps and 2 or more hormones
Hypothalamus- integrates nervous & endocrine systems |
|
|
Term
|
Definition
| stimulates the secretion and synthesis of one or more hormones at the anterior lobe |
|
|
Term
|
Definition
| Prevents the synthesis and secretion of hormones from the anterior lobe. |
|
|
Term
| hypophyseal portal system |
|
Definition
At the median eminence, (swelling near attachment of infundibulum), hypothalamic neurons release regulatory factors into interstitial fluids through fenestrated capillaries
Capillary networks supplied by superior hypophyseal artery
Unique structure: network of vessels (portal vessels) spiral around
infundibulum to the adenohypophysis, to a second capillary network
Ensures that regulatory factors reach intended target cells before entering general circulation |
|
|
Term
|
Definition
| - anterior lobe of the pituitary gland- releases 7 peptide hormones |
|
|
Term
|
Definition
| - posterior lobe of the pituitary gland- releases 2 peptide hormones |
|
|
Term
| 7 hormones from the anterior lobe |
|
Definition
| TSH,adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone, prolactin, growth hormone, and melanocyte-stimulating hormone. |
|
|
Term
|
Definition
Thyroid-stimulating hormone from the anterior lobe of the pituitary gland
stimulates the release of thyroid hormones
TSH is released in response to TRH from the hypothalamus.
As the levels of thyroid hormones rise, the the rates of TSH and TRH production decline |
|
|
Term
| ACTH (adrenocorticotropic hormone) |
|
Definition
Also known as corticotropin
Stimulates the release of steroid hormones by the adrenal cortex
ACTH targets cells that produce glucocorticoids
ACTH release occurs under the stimulation of corticotropin-releasing hormone from the hypothalamus
As glucocorticoid levels increase, the rates of CRH release and ACTH release decline. |
|
|
Term
| Follicle-stimulating hormone |
|
Definition
A gonadotropin, promotes follicle development in females, and, in combination with luteinizing hormone, stimulates the secretion of estrogens by ovarian cells.
In males, stimulates the secretion of Nurse cells |
|
|
Term
|
Definition
Induces ovulation, promotes ovarian secretion of estrogens and progesterones in females.
In males, stimulates production of androgens, most important testosterone. |
|
|
Term
|
Definition
| Stimulates mammary gland development along with other hormones; stimulates milk production |
|
|
Term
| Growth hormone (somatotropin) GH |
|
Definition
| Stimulates cell growth and replication by accelerating the rate of protein synthesis. |
|
|
Term
|
Definition
| In adipose tissue, GH stimulates the breakdown of stored triglycerides by adipocytes when release fatty acids into the blood. As circulating fatty acid levels rise, many tissues stop breaking down glucose to generate ATP and instead start breaking down fatty acids. |
|
|
Term
|
Definition
| In the liver, GH stimulates the breakdown of glycogen reserves by liver cells, which then release glucose into the bloodstream. |
|
|
Term
| Melanocyte-Stimulating Hormone |
|
Definition
| Secreted from the pars intermedia, stimulates production of melanin. Dopamine inhibits the release of MSH. |
|
|
Term
| Neurohypophysis (posterior lobe of the pituitary gland) |
|
Definition
| Contains the axons of hypothalamic neurons |
|
|
Term
|
Definition
| manufactures Antidiuretic hormone (ADH) |
|
|
Term
|
Definition
|
|
Term
| Antidiuretic hormone (vasopressin) |
|
Definition
| released in response to a rise in the solute concentration in the blood or a fall in blood volume or blood pressure. |
|
|
Term
|
Definition
| Specialized neurons in the hypothalamus that respond to a change in the osmotic concentration of body fluids. |
|
|
Term
|
Definition
To act on the kidneys to retain water and decrease urination.
Also causes vasoconstriction to help elevate BP.
Alcohol inhibits ADH release. |
|
|
Term
|
Definition
Stimulates smooth muscle contraction in the wall of the uterus; promotes ejection of milk.
Stimulates contractions of the ductus deferens and prostate gland |
|
|
Term
|
Definition
| Thyroxine (T4), epinephrine, norepinephrine, dopamine |
|
|
Term
|
Definition
small number of hormone molecules
bound to receptors may activate thousands of 2nd messengers |
|
|
Term
|
Definition
enzyme complex coupled to membrane
receptor, binds GTP
Link between 1st messenger and 2nd messenger
Activated when hormone binds to receptor at membrane surface
Changes concentration of 2nd messenger
Increased 2nd messengers accelerates metabolic activity within cell
cAMP or Ca2+ |
|
|
Term
|
Definition
Includes steroids & eicosanoids (cross directly), thyroid hormones (transport proteins)
Alter rate of DNA transcription in nucleus
Change patterns of protein synthesis
Directly affect metabolic activity and structure of target cell |
|
|
Term
| Complex commands are issued by: |
|
Definition
Continuously secreted, changes amount of hormone secreted
Insulin- rises & falls with blood glucose levels (humoral stimuli) |
|
|
Term
| hypothalamus releasing hormones which act upon adenohypophysis |
|
Definition
| Thyroid-releasing hormone (TRH) Releases thyroid-stimulating hormone (TSH) Corticotropin-releasing hormone (CRH) Releases adrenocorticotropic hormone (ACTH) Gonadotropin-releasing hormone (GnRH) Releases follicle-stimulating hormone (FSH), luteinizing hormone (LH) |
|
|
Term
|
Definition
hollow spheres lined by cuboidal epithelium
Cells surround follicle cavity that contains viscous colloid
Surrounded by network of capillaries that deliver nutrients and regulatory hormones & accept secretory products and metabolic wastes |
|
|
Term
| Follicle cells synthesize: |
|
Definition
thyroglobulin
Secreted into colloid of thyroid follicles
Molecules contain the amino acid tyrosine,
used to build thyroid hormones |
|
|
Term
|
Definition
Thyroid hormones activate genes code for synthesis of enzymes involved in glycolosis and ATP production.
Combined with mitochondria effects, increases metabolic rate of celll.
Cell consumes more energy resulting in increased heat generation.
Responsible for strong, immediate, and short-lived increase in rate of cellular metabolism. |
|
|
Term
| Clear cells (parafollicular cells) |
|
Definition
|
|
Term
|
Definition
| Hollow spheres lined by a simple cuboidal epithelium |
|
|
Term
|
Definition
Secreted by follicle cells into the colloid of the thyroid follicles.
Contains tyrosine |
|
|
Term
| Effects of thyroid hormone on peripheral tissues |
|
Definition
1. Elevated rates of oxygen consumption and energy consumption in children, may cause a rise in body temperature.
2. Increased heart rate and force of contraction, generally results in a rise in blood pressure.
3. Increased sensitivity to sympathetic stimulation.
4. Maintenance of normal sensitivity of respiratory centers to changes in oxygen and CO2 concentrations.
5. Stimulation of red blood cell formation and thus enhanced oxygen delivery.
6. Stimulation of activity in other endocrine tissues.
7. Accelerated turnover of minerals in bone. |
|
|
Term
|
Definition
Helps regulate Ca+ concentrations in body fluids.
-inhibits osteoclasts, which slows the rate of Ca+ release from bone
-stimulates Ca+ excretion by the kidneys
-stimulates bone growth and mineral deposition in the skeleton |
|
|
Term
|
Definition
Produce parathyroid hormone (PTH)
-2 pairs, embedded in the posterior surface of the thyroid gland |
|
|
Term
| Major effects of parathyroid hormones |
|
Definition
1. Stimulates osteoclast proliferation
2. Inhibits osteoblasts: reduces rate of calcium deposition in bone
3. Enhances reabsorption of Ca+ at kidneys, reducing urinary loss
4. Stimulates formation and secretion of calcitriol at kidneys.Effects complement PTH. Enhances Ca2+ PO4 absorption by digestive tract. |
|
|
Term
| Adrenal gland (suprarenal gland) |
|
Definition
Divided into 2 parts: Adrenal cortex and adrenal medulla
Sits on the superior border of each kidney near the level of the 12th rib |
|
|
Term
|
Definition
Produces corticosteroids
has 3 distinct zones
1.outer zona glomerulosa
2. middle zona fasciculata
3. zona reticularis |
|
|
Term
|
Definition
| Bound to transport proteins called transcortins |
|
|
Term
|
Definition
Outer region of suprarenal cortex
Produces mineralocorticoids |
|
|
Term
|
Definition
-stimulates conservation of Na+ and elimination of K+
-Retention of Na+ ions by the kidneys, sweat glands, salivary glands, pancreas, causes retention of water
-increases sensitivity of salt receptors in taste buds
-Secretion responds to drop in blood Na+, blood volume, or blood pressure or rise in blood K+ concentration
-release also occurs in reponse to angiotensin II |
|
|
Term
|
Definition
Produces glucocorticoids
-cortisol (hydrocortisone)
-corticosterone
Secretion regulated by negative feedback
-inhibitory effect on production of corticotropin-releasing hormone (CRH) in hypothalamus and ACTH in adenohypophysis
Accelerates glucose synthesis and glycogen formation
Anti-inflammatory effects-inhibits immune system |
|
|
Term
|
Definition
Network of endocrine cells, forms narrow band bordering each suprarenal medulla
Produces androgens under stimulation by ACTH
Adult females-promoting muscle mass, blood cell formation, libido |
|
|
Term
|
Definition
Secretions controlled by the sympathetic division of the autonomic nervous system
2 types of secretions:
-epiniphrine (adrenaline)
-norepinephrine (noradrenaline) |
|
|
Term
|
Definition
| About 75-80% of medullary secretions |
|
|
Term
|
Definition
| About 20-25% of medullary secretions |
|
|
Term
| Effects of activation of the adrenal medulla |
|
Definition
1.In skeletal muscle: triggers mobilization of glycogen reserves and accelerates the breakdown of glucose to provide ATP. This combination increases muscle strength and endurance.
2.In adipose tissue: stored fats are broken down into fatty acids, which are released into the blood stream for other tisues to use for ATP production.
3. In the liver: glycogen molecules are broken down. Glucose molecules released into the bloodstream for use by neural tissue which cannot shift to fatty acid metabolism.
4. In the heart: triggers an increase in the rate and force of cardiac muscle contraction. |
|
|
Term
|
Definition
Contains neurons, neuroglia, and pinealocytes
Lies in the posterior portion of the roof of the third ventricle |
|
|
Term
|
Definition
| Produce melatonin hormone from serotonin. Lowest during day, highest at night |
|
|
Term
|
Definition
-inhibiting reproductive functions-may play role in sexual maturation.
-protecting from free radicals-antioxidant, protect from nitric oxide or hydrogen peroxide
-setting circadian rhythms-daily changes in physiological processes that follow a regular day-night pattern. |
|
|
Term
|
Definition
Lies between inferior border of stomach and proximal portion of small intestine.
Contains both exocrine and endocrine cells
99% of pancreas: exocrine. Pancreatic acini (clusters of gland cells) |
|
|
Term
|
Definition
| consists of cells that form clusters known as pancreatic islets or islets of Langerhans |
|
|
Term
|
Definition
4 types of cells
Alpha:produces glucagon which raises blood glucose levels by increasing the rates of glycogen breakdown and glucose release by the liver.
Beta cells: produce insulin which lowers blood glucose levels. Increase rate of glucose uptake by body cells, increase rate glycogen synthesis in skeletal muscles and liver.
Delta cells: produce peptide hormone identical to growth hormone-inhibiting hormone, hypothalamic hormone. Suppresses release of glucagon and insulin by other islet cells, slows rate of food absorption and enzyme secretion along digestive tract
F cells: secrete pancreatic polypeptides (PP). Inhibits gallbladder contractions and regulates production of some pancreatic enzymes |
|
|
Term
|
Definition
| A peptide hormone released by beta cells when blood glucose concentrations exceed normal levels (70-110 mg/dL) |
|
|
Term
|
Definition
| Cells that have insulin receptors, most cells |
|
|
Term
| Insulin independent cells |
|
Definition
| Can absorb glucose without insulin stimulation-brain, kidney, RBCs, lining digestive tract |
|
|
Term
| Effects of insulin on target cells |
|
Definition
-Accelerating glucose uptake: results from an increase in the number of glucose transport proteins, these proteins move glucose into the cell by facilitated diffusion
-Accelerating glucose utilization and ATP production
-Stimulating glycogen formation (skeletal muscles and liver cells)
-Stimulating amino acid absorption and protein synthesis-helps maintain glucose levels by preventing the conversion of amino acids to glucose
-Stimulating triglyceride formation in adipose tissue-excess glucose used to synthesize triglycerides |
|
|
Term
|
Definition
| Released by alpha cells when glucose levels fall below normal to mobilize energy reserves |
|
|
Term
| Effects of glucagon on target cells |
|
Definition
-Stimulates breakdown of glycogen in skeletal muscle and liver cells
-Stimulates breakdown of triglycerides in adipose tissue into bloodstream
-Stimulates the production of glucose in liver-released into bloodstream-gluconeogenesis |
|
|
Term
|
Definition
Glucose levels so high they overwhelm re-absorption capabilities of kidneys
Type 1: do not produce insulin, autoimmune disease attacks beta cells
Type 2: produce insulin, receptor down-regulation |
|
|
Term
|
Definition
| A steroid hormone that is secreted by the kidneys in response to parathyroid hormone. |
|
|
Term
|
Definition
A peptide hormone released by the kidneys in response to low oxygen levels in kidney tissues.
-Stimulates the red bone marrow to produce red blood cells |
|
|
Term
|
Definition
Produced by juxtaglomerular cells in the kidneys in response to 1)sympathetic stimulation or 2) a decline in renal blood flow.
Once in the bloodstream, acts as an enzyme to start the renin-angiotensin-aldosterone system (RAAS) |
|
|
Term
|
Definition
ANP and BNP produced by the heart when blood volume becomes excessive, promotes loss of Na+ and water at kidneys
Inhibits secretion of renin and therefore angiotensin II, which increases blood volume
Resulting in reduction in blood volume and blood pressure |
|
|
Term
|
Definition
| Produced by the thymus, helps develop and maintain normal immune defenses |
|
|
Term
|
Definition
| produced by interstitial cells, support functional maturation of sperm, protein synthesis in skeletal muscle, secondary sex characteristics |
|
|
Term
| Nurse cells (sustentacular cells) |
|
Definition
secrete inhibin
-negative feedback-inhibin inhibits FSH secretion
-support differentiation and physical maturation of sperm |
|
|
Term
|
Definition
Produced by the ovaries
-supports follicle maturation, secondary sex characteristics
-after ovulation, follicle cells reorganize into corpus luteum which releases estrogens and progestins, especially progesterone
-Prepares uterus for implantation of egg, preps mammary glands for secretory activity |
|
|
Term
|
Definition
Secreted by adipose tissue, feedback control for appetite
-feeling of satiation, suppresses appetite
-controls normal levels of GnRH
Thin girls enter puberty later
increase in body fat increases fertility
Women stop menstruating when body fat becomes low |
|
|
Term
|
Definition
When 2 hormones have opposing effects, the net result depends of the balance between the 2 hormones. When 2 antagonistic hormones are present, the observed effects are weaker than those produced by either hormone acting unopposed.
Ex. Insulin and glucagon |
|
|
Term
|
Definition
| 2 hormones have additive effects so that the net result is greater than the effect that each would produce acting alone. Ex. glucose-sparing action of GH and glucocorticoids. |
|
|
Term
|
Definition
The first hormone is needed for the second to produce its effect.
Ex. epinephrine does not change energy consumption unless thyroid hormones are also present in normal concentrations |
|
|
Term
|
Definition
Hormones produce different but complementary results.
Ex. calcitriol and parathyroid hormone on tissues involved in calcium metabolism |
|
|
Term
| General Adaptation Syndrome (GAS) |
|
Definition
How body responds to stress-causing factors
1. Alarm phase
2. Resistance phase
3. Exhaustion phase |
|
|
Term
| Alarm phase (Fight or flight) |
|
Definition
Directed by the sympathetic division of ANS
-Energy reserves are mobilized
-body prepares for the stressor
-Epinephrine dominant hormone
Increased mental alertness, energy use
Mobilization of glycogen, lipid reserves
Reduce digestive activity, urine production
Sweating, increase in heart rate and breathing |
|
|
Term
|
Definition
Glucocorticoids are the dominant hormones.
GH, epinephrine, thyroid hormones involved
Higher than normal energy demands-glycogen already used up
-Mobilization remaining energy reserves-lipids, amino acids
-Conservation of glucose: peripheral tissues break down lipids to obtain energy
-Elevation of blood glucose concentrations-liver synthesizes glucose from other carbohydrates, amino acids, and lipids
-Conservation of salts and water, loss of K+ and H+. |
|
|
Term
|
Definition
Unless corrective actions are taken almost immediately, the failure of one or more organ systems will prove fatal.
-Exhaustion of lipid reserves
-Cumulative structural or functional damage to vital organs
-Inability to produce glucocorticoids
-Failure of electrolyte balance |
|
|
Term
|
Definition
| Sex hormones are produced at an inappropriate time, as early as age 5 or 6 |
|
|
Term
|
Definition
Anabolic steroids:
Suppress GnRH permanently, preventing normal production of testosterone forever
Liver dysfunction
Testicular atrophy-infertility |
|
|
Term
|
Definition
EPO used to increase number of blood cells, increase oxygen, increase ATP, increase performance.
-Blood becomes viscous which can result in heart failure or stroke |
|
|
Term
| GHB (Gamma-hydroxybutyrate) |
|
Definition
Date rape drug and sleeping aid
Raises growth hormone levels
Accompanied by an increase in levels of prolactin, counteracts many positive effects of elevated GH.
Report an increase in lean body mass and strength or accelerated fat loss. |
|
|
