Tubular Function

Question 1

Vasopressin is involved in

Answer 1

water balance, it increased reabsorption of water

Question 2

Aldosterone is involved in

Answer 2

sodium and potassium balance

Question 3

Angiotension II is involves in

Answer 3

sodium and acid-base balance

Question 4

Parathyroid hormone is involved in

Answer 4

calcium and phosphate

Question 5

What is reabsorbed in the proximal tubule?

Answer 5

water, sodium and potassium 70%

all the glucose and 75% bicarbonate

Question 6

What is reabsorbed in the Loop of Henle

Answer 6

15% water and bicarbonate, 20% sodium or potassium, no glucose

Question 7

What is reabsorbed in the Distal tubule and Collecting Duct

Answer 7

15% water, 10% sodium, bicarbonate, no glucose and excrete whatever is left of potassium

Question 8

Tubular Reabsorption and Secretion is driven by

Answer 8

Na-K-ATPase on the basolateral membrane

Question 9

Absorption into cell across lumenal membrane is _____ and driven by the _________ gradient of _______

Answer 9

passive, electrochemical, sodium

Question 10

Secretion across lumenal membrane into the tubule is _____ driven by _____ movement in the opposite direction

Answer 10

passive, sodium

Question 11

Transport of solutes coupled to sodium may be _____ an electrochemical gradient, called ______ active transport, but not ____

Answer 11

against, secondary, ATP

Question 12

Describ the Proximal Tubule.

Answer 12

Site of bulk absorption. uses NHE3 sodium transporter (used for bicarbonate reabsorption). Only place where glucose, aminoacid and phosphate cotransporters are located. and Very leaky.

Question 13

Describ the ascending limb to the loop of henle

Answer 13

reasorbs 20-30% sodium, transport protein NKCC2 (stopped by diruretic furosemide), impermeable to water, fluid leaving ascending limb is always less concentrated than plasma (passive diffusion by osmotic gradient)

Question 14

Describe DIstal Convolated Tubule

Answer 14

reabsords 5-10% sodium, sodium transporter NCC, inhibited by directics thiazides (less potent than furosemide)

Question 15

Collecting Duct

Answer 15

Reabsorbs 1-3% of filtered sodium, sodium channel ENaC, Aldosterone receptors= increases sodium reabsorption. Vasopressin receptors - increases water reabsorption
less permeable to cholride in order to secrete excess potassium SO it is the site of regulating the excretion of: Sodium, potassium, water and ammonium

Question 16

Describe early proximal tubule and glucose

Answer 16

uses SGLT II, one Na to one GLucose (not as strong absorption of glucose at the late proximal tubule

Question 17

Describe the late proximal tubule and glucose

Answer 17

uses SGLT I, one Na to Two Glucose, so it absorpbs the rest of the glucose so that there is none in the urine