Physiology of Adrenal Glands Flashcards
Where do the 2 adrenal glands lie?
Sit superior and medial to upper pole of kidneys
From the capsule down, what are the 3 layers of the adrenal cortex?
Zona glomerulosa
Zona fasiculata
Zona reticularis
What part of the adrenal gland is below the zona reticularis?
The medulla
m = middle
What does the zona glomerulosa produce and how is it regulated?
Produces mineralocorticoids and aldosterone
Aldosterone is regulated by K+ and ATII
What does the zona fasiculata produce and how is it regulated?
produces cortisol and glucocorticoids
regulated by ACTH
What does the zona reticularis produce and how is it regulated?
Produces androgens and DHEA
Regulated by ACTH
What 2 factors help regulate cortisol and androgen production?
CRH and ACTH
How is aldosterone regulated? and what activates it?
RAAS - activated in response to decreased blood ressure
When aldosterone is produced what does it allow the production of and what does this cause?
Production of ATII which causes direct (vasoconstriction) and indirect (aldosterone) methods of BP elevation
In bone and connective tissue, what does cortisol do?
Accelerates osteoporosis
decreases wound healing
decreases serum calcium
decreases collagen formation
What is the effect of cortisol on renal function and thus circulation?
Increases renal blood flow and GFR
Increases cardiac output
Increases BP
How does cortisol affect metabolism?
Increased blood sugar
Increased lipolysis, central redistribution
Increased proteolysis
What receptors does aldosterone bind to and where are they found?
Mineralocorticoid receptor/MRE
found in kidney, gut, salivary glands and sweat glands
What are the 3 effects produced by aldosterone when it binds to its receptor?
Na+/K+ balance
Blood pressure regulation
Regulation of extracellular volume
How is the adrenal medulla innervated?
Innervated by pre-synaptic fibres from sympathetic nervous system
