ENDO-adrenal glands Flashcards
what class of corticosteroid does the zona glomerulosa layer of adrenal cortex secrete?
mineralcorticoids
eg aldosterone
how is the zona glomerulosa arranged?
in spherical clusters and arched columns
what class of corticosteroid does the zona fasciculata layer of adrenal cortex secrete?
glucocorticoids
eg cortisol
how is the zona fasciculata arranged?
straight columns
what does the zona reticularis secrete?
androgens
how is the zona reticularis arranged?
branching cords
what does the renin-angiotensin-aldosterone system regulate?
blood pressure
describe the steps in the renin-angiotensin-aldosterone system?
- macula densa cells detect low Na+ conc
- baroreceptors detect drop in bp
- —->stimulates juxtaglomerular cells in kidneys to secrete RENIN
- —->stimulates liver to convert angiotensinogen to angiotensin 1
- —>ACE enzyme from the liver converts angiotensin 1 to angiotensin 2
- —>causes multiple effects
what are the effects of angiotensin 2?
- > Aldosterone production
- > Stimulates ADH release
- > Arterial vasoconstriction
- > Degrades Bradykinin
what is the effect of ADH secretion on blood pressure?
- > Cause increase in reabsorption of H2O
- > Thus increase in blood volume
- > Thus increase in blood pressure
what does aldosterone act on and what does it do?
->Acts on the distal tubules and collecting ducts of the kidney
->Increases Na+ reabsorption
Therefore increase in blood pressure
->Increase in potassium excretion
More potassium urinated out
how does arterial vasoconstriction affect blood pressure?
- > angiotensin2 acts on kidneys
- > Causes vasoconstriction of arterioles
- > More narrow vessel = more pressure
what is the role of bradykinin?
- > Bradykinin synthesizes nitric oxide (NO)
- >NO is a vasodilator
what is the effect of ACE on bradykinin and how does this affect blood pressure?
- > ACE degrades bradykinin
- >Thus less vasodilation so more vasoconstriction
what are the effects of cortisol on glucose?
- increase gluconeogenesis
- decrease hepatic glycogen synthesis
- inhibit peripheral glucose uptake
what are the effects of cortisol on lipids?
- increased appetite
- fat deposition
what are the effects of cortisol on protein?
- increased protein breakdown
- decreased protein production
what are the effects of cortisol on ions?
- increased sodium retention
- increased potassium loss
- anti-inflammatory effects
what are the effects of cortisol on stress resistance?
Glucocorticoids make blood vessels more sensitive to vasoconstricting hormones, raising blood pressure
what are the effects of cortisol on immunity?
High doses of glucocorticoids suppress immune response
describe the regulation of cortisol
low cortisol—>ACTH produced by anterior pituitary—->travel to zona fasciculata—>cause cortisol production—->until cortisol returns to normal
what type of feedback is the regulation of cortisol?
negative
what are the functions of androgens?
- in females->promote libido and converted to estrogens
- > after menopause all female estrogens come from conversion of adrenal androgens
- stimulate axillary and pubic hair growth in boys and girls
- contribute to prepubertal growth spurt
what is the main purpose of the adrenal medulla?
- produce catecholamines
- > noradrenaline
- > adrenaline
