Adrenal Physiology

Question 1

What happens when the hypothalamus receives signals of stress

Answer 1

releases CRH, which binds to receptor on ant. pit. corticotrophic cells

Question 2

What does CRH binding to anti pit. corticotrophic cells lead to

Answer 2

exocytosis of ACTH which binds to meanocortin 2 receptor (MC2R) on plasma membrane of adrenal cortex

Question 3

What does binding of ACTH to MC2R elad to

Answer 3

increase serum cortisol levels

ACTH released in pulsatile fashion

Question 4

How does cortisol exert neg feedback

Answer 4

inhibits synthesis of CRH and ACTH

Question 5

main steriod hormones producted from zona glomerulosa

Answer 5

mineralcorticoid - aldosterone

Question 6

main steroid hormones produced form zona fasciculata

Answer 6

flucocorticoids - cortisol and corticosterone

Question 7

main steroid hormones produced from zona reticularis

Answer 7

androgens - DHEA, and androstenedione

Question 8

affect of aldosterone

Answer 8

Increases blood vol. and pressure. Increases Na and H2O reabsorption and decreases K reabsorption.

Question 9

affect of cortisol

Answer 9

increased blood glucose, inhibits immune system, decreases fibroblast proliferation

Question 10

how does cortisol increase plasma glucose levels in the liver

Answer 10

Increased gluconeogenesis and glycogenesis

Question 11

how does cortisol increase plasma glucose levels in skel. muscle

Answer 11

decreased gluc uptake and increased glycogenesis and protein catabolism

Question 12

how does cortisol increase plasma glucose levels in adipose

Answer 12

decreased gluc uptake and increase lipolysis.

Question 13

Describe the mechanism by which aldosterone increases water and sodium reabsorption.

Answer 13

Binds to and activates mineralocorticoid receptors (MR) in distal convoluted tubule and collecting ducts cytoplasm. MR translocates to nucleus to increase gene transcription of ENaC and Na/K pumps. ENaC transports Na into cell and Na/K ATPase transports it out to blood. Water follows Na.

Question 14

what catecholamines are released by the adrenal medulla

Answer 14

epinephrine and norepinephrine

Question 15

how can cortisol regulate epinephrine

Answer 15

increases the enzyme that converts norep. into ep.

Question 16

how does cortisol facilitate the effects of norepinephrine and epinephrine

Answer 16

induces expression of receptors for norep. and ep

Question 17

what can cause cushing disease

Answer 17

pituitary hypersecretion of ACTH
adrenal ademona
ectopic ACTH production (lung cancer)
perscribing cortisol

Question 18

what causes addison’s disease

Answer 18

autoimmune (can be caused by TB) destruction of adrenal cortex zones. Deficiency in cortisol, aldosterone, and androgens.

Question 19

ACTH and CRH levels in addison’s disease

Answer 19

high

Question 20

waht are teh symptons of addisons

Answer 20

hypo tension

Question 21

what are the signs of addisons

Answer 21

Hypoglycemia, hyponatremia, hyperkalemia, wt loss, hyperpigmentation,

Question 22

what is secondary adrenal insufficiency caused by

Answer 22

pituitary or hypothalamic disorders or chronic glucocorticoid therapy

Question 23

what happens in 21-hydroxylase deficiency

Answer 23

aldosterone and cortisol can’t be formed

Question 24

what are the symptoms of 21-hydrozylase deficiency

Answer 24

Females w/ male genitalia, males with adult size sex organs. Aldosterone deficiency can lead to salt wasting – shock and dehydration.