ECF volume regulation

Question 1

what cells produce renin?

Answer 1

juxtaglomerular cells of the afferent arteriole

Question 2

where is ADH produced from?

Answer 2

supraoptic and paraventricular nuclei of hypothalamus

Question 3

what are the functions of angiotensin II?

Answer 3

potent vasoconstrictor
acts on the proximal tubule to increase NaCl and H20 reabsorption
increases aldosterone production
increases thirst & salt cravings in hypothalamus
stimulates ADH release

Question 4

does the GFR directly correlate to the blood pressure?

Answer 4

no because due to autoregulation the GFR is able to be maintained even when blood pressure is too low;
achieved by constricting efferent arterioles to increase hydrostatic pressure

Question 5

what forms the juxtoglomerulus apparatus?

Answer 5

juxtaglomerular cells of afferent arterioles

macula dense of ascending loop of henle

Question 6

what is the function of the juxtaglomerular apparatus?

Answer 6

macula densa detect an increase in NaCl delivery through the ascending loop of henle
this then sends signals to the juxtaglomerular cells to inhibit the release of renin

Question 7

what increases renin release?

Answer 7

increased sympathetic nerve activity via B1
decreased pressure delivery at the juxtaglomerular cells
decreased NaCl delivery to macula densa

Question 8

what inhibits renin release?

Answer 8

Angiotensin II via negative feedback

ADH

Question 9

what counteracts the effects of aldosterone?

Answer 9

atrial natriuretic peptide (ANP)

Question 10

how does hyperglycaemia result in coma?

Answer 10

increased glucose in proximal tubule creates osmotic effect driving water in
this diminishes the interstitial oncotic pressure therefore the urine isn’t concentrated in the ascending loop of henle (NaCl isn’t reabsorbed)
high amounts of naCl are detected by the macula densa therefore decreasing renin - this then causes even less NaCl to be absorbed - decreased BP
significant hypotension occurs = reduced brain perfusion = coma