Renal Transport Processes

Question 1

What cellular changes are evident from S1 to S3 segments of the proximal tubule?

Answer 1

Brush border becomes progressiely deeper

Mitochondrial concentration decreses

Question 2

What is the major extracellular cation?

Answer 2

Sodium

Question 3

What does the proximal tubule reabsorb (and their respective amounts)?

Answer 3

Na and Water - 65-70%

K - 80-85%

Cl - 65%

Phophate - 75-80%

Glucose - 100%

Amino acids - 100%

Question 4

What nephron segments reabsorb sodium?

Answer 4

Proximal convoluted tubule (S1 and S2)

Proximal straight tubule (S3)

Thin descending limb

Thick ascending limb

Distal tubule

Collecting tubule

Question 5

How does the PCT (S1 and S2) reabsorb sodium?

Answer 5

Bulk flow via secondary active sodium otransport with several substances (glucose, amino acids, phosphate, and organic acids)

Na / H antiporters

Question 6

How does the proximal straight tubule (S3) reabsorb sodium?

Answer 6

Na / H antiporters

Question 7

How much of the sodium filtered load is reabsorbed in the whole proximal tubule?

Answer 7

65-70%

Question 8

How does the thin descending limb reabsorb sodium