Lecture 4 - Nephron Function I

Question 1

Extrinsic mechanisms of renal autoregulation?

Answer 1

Renin-Angiotensin II (constriction of efferent, increase), ANP & BNP (dilation of afferent, increase), sympathetic nervous system (constriction of afferent, decrease)

Question 2

Intrinsic mechanisms of renal autoregulation?

Answer 2

myogenic (offsets pressure increase, keeps flow stable), macula densa cells detecting high NaCl in distal tubule (constrict afferent, decrease to restore)

Question 3

Transport mechanisms of proximal tubule?

Answer 3

primary active transport (ATP), secondary active transport (co-transport) and passive paracellular

Question 4

Reabsorption of bicarbonate by proximal tubule?

Answer 4

Na uptake drives H+ release into lumen, pH drop leads to ncreased bicarbonate absorption as CO2, forms H+ and HCO3-, bicarbonate transported across basolateral membrane

Question 5

Chloride reabsorption in distal tubule?

Answer 5

concentrated due to prior water and solute reabsorption, moves down conc gradient via tight junctions, electropositive lumen induces paracellular reabsorption