Lecture 7 Regulation of ECF Volume 1

Question 1

What is the distribution of body water

Answer 1

2/3 = ICF
1/3 = ECF

Question 2

When there is reduced ECF what changes are seen in the kidney

Answer 2

• Increase in sympathetic discharge
• Increase in renal vascular conductance nerve activity  increase in renal arteriolar constriction and increase in renin
• Increase in renin  increase in angiotensin II  decrease in peritubular capillary hydrostatic pressure and oncotic pressure increases  Na+ resorption from the proximal tubule and less Na+ excreted
• Increase in renin  angiotensin II increase in aldosterone  increase in distal tubule Na+ reabsorption and less Na+ is excreted

Question 3

Smooth muscle of the media of the afferent arteriole, just before it enters the glomerulus is specialised how?

Answer 3

Contains large epithelial cells with plentiful granules = Juxtaglomerular cells

Question 4

What makes up the juxtaglomerular apparatus

Answer 4

Maula densa in distal tubules and afferent arterioles

Question 5

What hormone does JG cells produced

Answer 5

Renin

Question 6

What is the action of renin

Answer 6

Converts angiotensin to angiotensin I

Question 7

What is the action of ACE

Answer 7

Converts Angiotensin I to angiotensin II

Question 8

Where is ACE found

Answer 8

vascular endothelium

Question 9

Once ACE creates Angiotensin II what is stimulated

Answer 9

Released of aldosterone from the Zona glomerulosa in the adrenal cortex and stimulates Na+ reabsorption

Question 10

What controls Renin release

Answer 10

Pressure change in afferent arterioles decrease (less distention)
Increase in sympathetic nerve activity via B1 effect