BP control

Question 1

What are the regions of the adrenal cortex and what do they secrete?

Answer 1

GFR-ACD
zona Glomerulosa = Aldosterone
zona Fasciculata = Cortisol
zona Reticularis = DHEA

Question 2

What is renin released by?

Answer 2

Renal juxtaglomerular cells

Question 3

What factors stimulate renin secretion?

Answer 3

Mainly reduced renal perfusion (aka hypotension)
Hyponatraemia, sympathetic nerve stimulatio n

Question 4

What is the function of renin?

Answer 4

Hydrolyses angiotensinogen to angiotensin I

Question 5

What is the function of angiotensin converting enzyme?

Answer 5

Converts angiotensin I to angiotensin II

Question 6

What does angiotensin II do?

Answer 6

Vasoconstriction of vascular smooth muscle –> increased BP
Vasoconstriction of efferent arteriole of glomerulus –> increased filtration fraction to preserve GFR
Stimulates thirst
Stimulate aldosterone and ADH release
Invcerase proximal tubule Na/H activity

Question 7

What is aldosterone secreted in response to?

Answer 7

Angiotensin II
Potassium levels
ACTH

Question 8

What is the function of aldosterone?

Answer 8

Causes retention of Na in exchange for K/H in distal tubule

Question 9

What is the function of ADH?

Answer 9

Promotes water reabsorption in collecting ducts of kidneys

Question 10

How does ADH promote reabsorption of water?

Answer 10

Insertion of aquaporin-2 channels

Question 11

Where is ADH synthesised and secreted from?

Answer 11

Synthesised by hypothalamus
Released by posterior pituitary