RNU week 3

Question 1

mesangial cells

Answer 1

lie between capillaries. Contain actin and can contract when in response to flow.
They permit control of capillary diameter

Question 2

juxtaglomerular apparatus

Answer 2

the juxtaglomerular cells - located in the afferent arteriole and produce renin
macula densa - located in DCT and senses flow within the tubule. CAN produce adenosine which causes constriction of afferent arteriole

Question 3

PCT

Answer 3

75-80% of filtered fluid reabsorbed here. Glucose, phosphate, chloride, bicarbonate, phosphate, potassium and water

Question 4

% of body weight that is water

Answer 4

60%

Question 5

% of water that is intracellular

Answer 5

40%

Question 6

glomerular filtration barrier

Answer 6

specialised capillary endothelium, glomerular BM (with collagen type IV), podocyte foot processes

Question 7

Acute kidney injury

Answer 7

abrupt loss of kidney function that develops within 7 days

Question 8

loop diuretics

Answer 8

act on NK2Cl channel. Loss of 15-25% of water in filtrate. Uses - oedema, hypercalcaemia, hypertension, CKD. Increases excretion of Mg, Ca, K+. Ototoxic at high doses.
Have a short, but rapid response, with a steep dose response. They are effective in renal failure. Can cause metabolic alkalosis
e.g. frusemide, bumetanide

Question 9

Thiazides

Answer 9

act on Na/Cl co-transporter in DCT. 5-15% loss of sodium/water. Slow absorption. Increase Mg, K= excretion, decrease Ca excretion. Used for hypertension, oedema, hypercalciuria.
Not effective in CKD
E.g. bendrofluamethiazide

Question 10

K+ sparing diuretics

Answer 10

Block the ENaC channel. About 5% loss of sodium/water. Affects the DCT and collecting duct. Used in K+ conserving areas, oedema, heart failure, cirrhosis - hyperaldosterone states .
Dangerous in CKD due to potential hyperkalaemia
E.g. spirinolactone