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Hypothalamus and Pituitary Gland
Hypothalamus and Pituitary Gland
103
Physiology
Undergraduate 3
07/21/2012

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Term
Where is the hypothalamus?
Definition
brain
Term
What are the two lobes of the pituatary gland?
Definition
anterior lobe and posterior lobe
Term
What is the infundibulum?
Definition
thin stalk of tissue connecting pituitary and hypothalamus
Term
Two Hormones of posterior pituatary:
Definition
antidiuretic hormone (ADH/vasopressin)
oxycotin
Term
Antidiuretic hormone purpose:
Definition
water balance and osmolarity
Term
oxycotin purpose:
Definition
milk ejections, contraction of uterus, behavioral functions (bonding)
Term
Posterior pituatary is continuous with
Definition
hypothalamus of the brain
Term
Posterior pituatary hormones are secreted by
Definition
special neurons (neurosecretory neurons) whose cells bodies are located in hypothalamus whose axons travel into Posterior pituatary
Term
How is the Anterior pituitary connected to hypothalamous?
Definition
Not directly, but through the hypothalamic/pituitary portal system.
Term
what is the hypothalamic/pituitary portal system?
Definition
one capillary network in the hypothalamus, one in the Anterior pituitary. Portal vessles link two capillary beds.
Term
Cells in Anterior pituitary secrete how many hormones?
Definition
6
Term
Secretion of Anterior pituitary hormones is controlled by-
Definition
hormones from hypothalamus
Term
Anterior pituitary hormones
Definition
follicle stimulating hormone (FSH)
luteinizing hormone
prolactin (breast development in pregnancy)
Adrenocorticotropic hormone
Growth hormone
thyroid stimulating hormone
Term
Prolactin:
Definition
causes breast development during pregnancy
Term
adrenocorticotropic hormone
Definition
stimulated adrenal cortex to secrete cortisol
Term
growth hormone
Definition
regulates overall body growth
Term
thyroid stimulated hormone
Definition
stimulates thyroid gland to secrete thyroxine
Term
What regulates the secretion of hormones from the anterior pituitary gland?
Definition
tropic hormones of hypothalamus
Term
Two general categories of tropic hormones?
Definition
releasing and inhibiting hormones
Term
Which hormones stimulate secretion of Anterior pituitary hormones
Definition
5 Releasing Hormones
Term
5 releasing hormones:
Definition
1 gonadotropin- controls FSH and LH
2 prolactin- controls prolactin
3 corticotropin- controls ACTH
4 growth hormone- controls growth hormone
5 thryrotropin controles TSH
Term
What prevents secretion of Anterior pituitary hormones?
Definition
Inhibiting hormones
Term
What is the tropic hormone pathway?
Definition
hypothalamus secretes releasing or inhibitng hormone- enters blood- goes to portal system- travel to Anterior pituitary secretory cells- alter secretion of Anterior pituitary hormones- those enter blood stream- travel to target tissues
Term
Control of hypothalamic tropic hormone release-
Definition
neural input
negative feedback
circadian rythm
Term
Neural Input on Control of hypothalamic tropic hormone release
Definition
ex: stress can stimulate release of corticotropin releasing hormone
Term
Negative Feedback of Control of hypothalamic tropic hormone release
Definition
hormones feedback on hypothalamus
Term
Circadian rythm of Control of hypothalamic tropic hormone release
Definition
secretion in cycles repeated each day.
Growth hormone released at night
Term
Endocrine control=
Definition
hormonal control
Term
Hormones=
Definition
regulatory molecules secreted by cells at one site in the body which travel in the blood to influence cells at a different. Long distance communication
Term
Thyroid hormone is produced by
Definition
thyroid gland which is located over pharynx in neck
Term
Iodide atoms are in -- and obtained by --
Definition
thyroid, from diet
Term
Type of transport of thyroid hormone from blood int thyroid gland?
Definition
Actively transported.
Term
What can be used to destroy thyroid tissue in hyperthyroidism?
Definition
Radioactive thyroid
Term
Are there any more functions of iodine in our bodies?
Definition
No, only known function is thyroid hormone
Term
Number of forms of thyroid hormone-
Definition
Two primary
T4 and T3
Term
T4 thyroid hormone:
Definition
contains 4 iodide atoms
most abundant form produced
least active
provides long loop negative feedback
Term
T3 thyroid hormone:
Definition
contains 3 iodide atoms
not as much made
most active form of thyroid form
Term
Activation of thyroid hormone in target tissue:
Definition
T4 is mostly converted to T3, and effects are mostly due to T3
Term
What cells are affected by thyroid hormone?
Definition
Virtually all cells in body
Term
Thyroid hormone (increased or decreased) metabolic rate, meaning (more or less) ATP utilization
Definition
Increased
More Energy
Term
Thyroid hormone effects on heat production
Definition
increased
Term
thyroid hormone effects on heart rate/ contraction force of heart
Definition
increased- heart cells more responsive to Norepinephrine and epinephrine
Term
Decreased thyroid hormone from birth=
Definition
leads to cretinism, small mental retardation
Term
Thyroid hormone is necessary for
Definition
proper growth and development of nervous system
Term
Hyperthyroidism=
Definition
excess thyroid hormone
Term
Hyperthyroidism caused by-
Definition
either hypersecretion from thyroid or increased TSH from anterior pituitary or increased thryotropin releasing hormone from hypothalamus.
Term
Symptoms of Hyperthyroidism
Definition
fever, increased breakdown of proteins and fat, decreased body weight, increased heart rate, nervous system (anxious, tense, irritable) goiter- enlarged thyroid gland
Term
Gave's disease=
Definition
Hyperthyroidism caused by autoimmune disease
body makes an abnormal antibody that directly stimulates thyroid gland to secrete thyroid hormone.
Same Hyperthyroid problems + bulging eyes
Term
Growth Hormone (GH) causes increased
Definition
growth in most body tissues
Term
Growth Hormone (GH) is released from
Definition
anterior pituitary (growth hormone released from hypothalamus releases growth hormone from anterior pituitary)
Term
Number of spurts of Growth Hormone (GH) released throughout life
Definition
2 postnatal and puberty.
However it is secreated throughout
Term
Growth Hormone (GH)secretion declines
Definition
with age
Term
hypertrophy
Definition
increased cell size
Term
hyperplasia
Definition
increased cell number
Term
growth hormone is responsible for
Definition
hypertrophy, hyperplasia, stimulating protein sythesis
Term
Growth Hormone (GH) -- bones in both :
Definition
increasd growth in length and thickness.
stimulates cells in epiphyseal plates of long bones. Increased deposition of cartilage/bone
Term
Epiphyseal plate-
Definition
site of growth
cartilage
Term
Are most growth effects a direct action of growth hormone?
Definition
No
Term
Growth Hormone (GH) -- glucose uptake into adipose tissue and skeletal muscle
Definition
inhibits
Term
Growth Hormone (GH) -- lipolysis in adipose tissue and gluconeogenesis in liver
Definition
stimulates
Term
Growth Hormone (GH) -- uptake of amino acids into cells
Definition
increases
Term
What does Growth Hormone (GH) stimulate, and what does that secrete?
Definition
Liver cells to secrete molecules called somatomedins (insulin-like growth factors)
Term
Most growth effects are due to?
Definition
Somatomedins- they have direct effect on target cells
Term
Does Growth Hormone (GH) have some direct on tissues?
Definition
Yes, but most growth is through actions of somatomedins
Term
Effects of abnormal Growth Hormone (GH) secretion-
Definition
gigantism
acromegaly
dwarfism
Term
Gigantism is increased Growth Hormone (GH) when?
Are body features proportionate?
Definition
increased GH secreion in children, before puberty.
Proportioned body
Term
Acromegaly is increased Growth Hormone (GH) when? What does it cause? Is body in proportioned or disfigured?
Definition
Increased Growth Hormone (GH) in adults after puberty. Causes bone thickening not length, disfugering condition
Term
Dwarfism is decreased Growth Hormone (GH) when? What does it cause?
Definition
decreased Growth Hormone (GH) secretion or failure of cells to respond to Growth Hormone (GH) and or somatomedins in Children.
The Long bones (legs arms fingers) are shortened
Term
Is achondroplasia (short arms and legs, torso is normal) related to abnormal Growth Hormone (GH)?
Definition
no
Term
Other Hormones than Growth Hormone (GH) that affect Growth include:
Definition
Thyroid Hormones
Insulin
Sex hormones
Glucocorticoids
Term
How do thyroid hormones affect growth?
Definition
Required for synthesis of Growth Hormone (GH). Permissive for Growth Hormone (GH) actions
Term
How does insulin affect growth?
Definition
Permissive for Growth Hormone (GH) actions
Term
How do sex hormones affect growth?
Definition
Actively promotes and is Important for pubertal growth spurt, little role in childhood growth.
Term
How do glucocorticoids affect growth?
Definition
Inhibit growth.
Term
What cells secrete cortisol?
Definition
Adrenal Cortex
Term
What stimulates the secretion of cortisol?
Definition
ACTH from anterior pituitary
Term
What is cortisol derived from?
Definition
Cholesterol
Term
What type of hormone is cortisol classified as?
Definition
A steroid hormone
Term
What is cortisol also known as? What does it affect?
Definition
glucocorticoid, affects blood glucose levels
Term
What is the primary action of cortisol?
Definition
increase blood glucose concentration
Term
What actions does cortisol take to increase blood glucose concentration?
Definition
Increases gluconeogensis in liver
Increases protein breakdown- amino acids can be used in gluconeogensis
Increases fat breakdown- fatty acids can be used by most cells for energy.
Term
What type of control does cortisol have on blood glucose?
Definition
long term
Term
What is the hormone of stress?
Definition
cortisol
Term
What happens to cortisol levels during times of stress (physical and psychological)? What does this do?
Definition
They increase to mobilize energy stores
Term
High concentrations of cortisol prevent?
Definition
inflamation
Term
Are the anti-inflammatory affects of cortisol at physiological levels?
Definition
No
Term
What derivatives of cortisol are used to treat inflamation?
Definition
prednisone
Term
What can cortisol supress?
Definition
Immune response
Term
Is the immune system suppressed at physiological levels?
Definition
yes
Term
What autoimmune diesease is cortisol used to treat?
Definition
lupus
Term
Effects of abnormal glucocorticoid secretion?
Definition
cushings syndrom and addisons disease
Term
What is cushing's syndrom?
Definition
Hypersecretion of cortisol.
Hyperglycemia
Protein depletion- wasting away of muscle, especially in arms and legs.
Deposition of fat in belly and face
Degerneration of capillaries (causes local hemorrhages)
Bruising, striae (streaks) on abdomen
Term
What is addisons disease?
Definition
hyposecretion
Term
Parathyroid Hormone (PTH) is secreted from?
Definition
Parathyroid glands (4 small glands around thyroid gland)
Term
What are the functions of Parathyroid Hormone (PTH) ?
Definition
increase concentration of blood calcium
Term
Stimulus for Parathyroid Hormone (PTH)?
Definition
low blood calcium
Term
What are the direct actions of Parathyroid Hormone (PTH) ?
Definition
-Increase the release of calcium from bone (major storage site for calcium)
-Also prevents calcium excretion by kidney
Term
What percentage of calcium in body is stored in bone?
Definition
99%
Term
How does Parathyroid Hormone (PTH) increase the release of calcium from bone?
Definition
Causes specialized bone cells (oseoclasts) to dissolve a small amount of bone, thus releasing it into blood
Term
How does Parathyroid Hormone (PTH) prevent excretion of calcium?
Definition
Makes more calcium reabsorbed by nephron and returned to blood
Term
What do osteoporosis drugs prevent?
Definition
The activity of osteoclasts
Term
What are the indirect actions of Parathyroid Hormone (PTH) ?
Definition
indirectly increases absorption of calcium in digestive tract into blood by directly increasing the activation of vitamin D3 in kidney cells.
Term
What does active vitamin D3 do?
Definition
Active D3 increases the absorption of ingested calcium in small intestine
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