Proximal Convoluted Tubule

Question 1

What is reabsorbed at the PCT?

Answer 1

Glucose 
AA
Na+
Cl-
Water
HCO3-
Phosphate
Lactate

Question 2

What does the PCT secrete?

Answer 2

Organic ions

Question 3

What happens In the PCT?

Answer 3

Bulk reabsorption

Question 4

What happens in bulk reabsorption?

Answer 4

Primary AT- transport of Na+ basolaterally into IF
3Na+ out, 2K+ in
Na+/K+ ATPase pump basolaterally-builds a conc gradient of Na+ (lumen) into PCT lining cells
Secondary AT - Na+ cotransports glucose, AA and lactose into cell
Na+ antiported with H+ (to maintain charge) - Na+ in, H+ out

Question 5

As Na+ and other ions are reabsorbed, what happens to water?

Answer 5

Water follows passively by osmosis

Question 6

What happens in HCO3- reabsorption?

Answer 6

Tubular Na+/H+ antiporter, H+ + HCO3- in lumen into H2CO3 into H2O + CO2
CO2 diffuses into PCT cell, reacts with H2O in cell
CO2 + H2O —> H2CO3 —> H+ + HCO3-
H+ antiported back to lumen
HCO3- basolaterally facilitated diffusion into capillary

Question 7

More glomerular filtrate = ….. PCT absorption

Answer 7

Increased