3 filtration, secretion, absorption

Question 1

the nephrons in the 2 kidneys of a typical adult filter about how many litres of plasma a day ?

Answer 1

180

Question 2

Filtration is a passive process whereby ….

Answer 2

water and small molecules are driven through a selective filter by a gradient of hydrostatic pressure
occurs in the glomerulus

Question 3

Name 2 glomerular diseases

Answer 3

• goodpasture syndrome
• alport syndrome

Question 4

Glomerular diseases such as goodpasture & alport syndrome that lead to ….

Answer 4

damage to the basement membrane so that protein may leak through the filter and appear in the urine - proteinuria

Question 5

PCT…

Question 6

Descending limb of LOH…

Question 7

thin ascending limb of LOH…

Question 8

thick ascending limb of LOH

Question 9

early DCT…

Question 10

late DCT…

Question 11

collecting duct …

Question 12

what are the 2 main cell types in the region of the DCT and collecting duct ?

Answer 12

1. principal cells
2. intercalated cells

Question 13

what are principal cells involved in ?

Answer 13

Involved in the uptake of sodium ions and the extrusion of potassium ions.

Driven by a Na+/K+-ATPase on the basolateral membrane.

Question 14

what are intercalate cells involved in ?

Answer 14

Assist in acid-base control, by controlling the levels of hydrogen (H+) and bicarbonate ions (HCO3–)

Question 15

renal clearance is what?

Answer 15

volume of plasma from which a substance is completely removed (cleared) by the kidneys per unit time

Question 16

equation for renal clearance ? & what does each factor mean ?

Answer 16

Cx = clearance
Ux = conc. of X in urine
V = volume of urine formed in given time (urine flow rate)
Px = conc. of X in systemic blood plasma

Cx = ( Ux * V ) / Px

Question 17

for what substances can the clearance rate be used to estimate the glomerular filtration rate (GFR) ?

Answer 17

• certain substances like inulin or creatinine
• they are freely filtered by the glomerulus and not reabsorbed or secreted by the tubules