Lecture 16 - Tubular Reabsorption and Secretion

Question 1

Sodium channels found in apical membrane of all nephron cells

Answer 1

ENaC channel (epithelial Na Channel)

Question 2

Chrloride and K+ channels are found in the ____ membranes of all nephron cells.

A. Apical
B. Basolateral
C. Basal
D. Lateral

Answer 2

A. apical (facing the lumen)

Question 3

Contain numerous mitochondria and have extensive brush borders. 
A. PCT
B. DCT
C. Loop of Henle
D. Collecting Tubule

Answer 3

A. PCT

Question 4

The cells of the PCT resorb ____ of Na, Cl, H2CO3, and K.

Answer 4

65%

Question 5

The cells of the PCT resorb ____ of glucose and amino acids.

Answer 5

100%

Question 6

The PCT cells are responsible for the (secretion/resorption) of acids, bases, and H+ ions.

Answer 6

secretion

Question 7

The PCT cells resorb Na along with \_\_\_\_\_\_ through co-transport.
A. Cl-
B. Organic Acids, organic bases
C. glucose, AAs
D. K+, H2CO3

Answer 7

C. glucose, AAs

Question 8

The second half of the PCT resorbs Na via \_\_\_\_\_\_.
A. Anti-transport of K+
B. Co-transport of K+
C. Anti-transport of Cl-
D. Co-transport of Cl-

Answer 8

D. Co-transport of Cl-

Question 9

The PCT works with anti-port transporters to secrete \_\_\_\_\_\_\_\_ into the tubular lumen.
A. Cl-
B. HCO3
C. H+
D. K+

Answer 9

C. H+

Question 10

The thin descending segment of the Loop of Henle is highly permeable to ________.

A. Urea
B. Sodium
C. Water
D. Cl

Answer 10

C. Water

Question 11

The thin descending segment of the Loop of Henle is moderately permeable to ________.

A. Urea
B. Sodium
C. Water
D. Cl
E. A & D
F. A & B

Answer 11

F. A & B

Question 12

The thick ascending limb of the loop of Henle is responsible for the secretion of _____________.

A. H+
B. Mg 2+
C. Na+
D. K+

Answer 12

A. H+

Question 13

The thick ascending mechanism establishes a NaCl gradient through apical ______.

a. ENaC
B. Na/K pumps
C. Na/2Cl/K channel
D. K+ channels

Answer 13

C. Na/2Cl/K channel

Question 14

The ascending limb of the Loop of Henle utilizes what mechanism for chloride resorption?

Answer 14

1) Na/2Cl/K pump into tubular epithelial cell

2) K+ diffuses through channel into the interstitial fluid

Question 15

Na/KATPase is located on the ____ side of the ascending limb of the Loop of Henle.

a. apical
b. basolateral

Answer 15

b. basolateral

Question 16

The +8mV charge of the tubular fluid is produced primarily by _________.

a. diffusion of H+ into the tubular lumen
b. Na/H co-transport of H+ into the tubular lumen
C. Na/K ATPase moving K+ into the tubular lumen
D. Diffusion of K+ into the tubular lumen

Answer 16

D. diffusion of K+ into the lumen

Question 17

Why is the basolateral Na/KATPase important in the thick ascending loop?

Answer 17

The basolateral Na/KATPase acts to pump Na into the renal interstitium (against the Na gradient). This allows the diffusion of Na from the renal tubule. This Na movement is accomplished through a Na/H counter-transport, permitting H+ secretion and eventual excretion.

Question 18

The thin ascending segment of the Loop of Henle is (permeable/impermeable) to water.

Answer 18

impermeable (allows for concentration of urine and establishment of the counter-current multiplication system)

Question 19

Widespread aquaporin, including within the renal tubules.

A. Aquaporin-1
B. Aquaporin-2
C. Aquaporin-3

Answer 19

A. Aquaporin-1

Question 20

Aquaporin within the basolateral membrane of the collecting tubules.

A. Aquaporin-1
B. Aquaporin-2
C. Aquaporin-3

Answer 20

C. Aquaporin-3

Question 21

Aquaporin located in the apical membrane of the collecting tubule. Is sensitive to ADH.

A. Aquaporin-1
B. Aquaporin-2
C. Aquaporin-3

Answer 21

B. Aquaporin-2

Question 22

Primary active transporters utilize ____ directly to move a solute ____ a concentration gradient.

Answer 22

ATP; against

Question 23

The PCT utilizes secondary active transport to reabsorb ________.

A. amino acids and glucose
B. organic acids and glucose
C. sodium and amino acids
D. water and glucose

Answer 23

A. amino acids and glucose

Question 24

What solutes are actively secreted into the renal tubules?

Answer 24

creatine and para-aminohippuric acid

Question 25

Two factors affect the rate of transport of substances out of the tubule. What are they?

Answer 25

electrochemical gradient and time in the tubule

A high electrochemical gradient increases the likelihood of diffusion.

A rapid renal tubule flow will decrease the time that the solute spends in a given area of the tubule.

“Time-gradient diffusion”

Question 26

The source of aldosterone is:

A. Adrenal cortex
B. Anterior pituitary
C. Posterior pituitary
D. Hypothalamus

Answer 26

A. Adrenal cortex

Question 27

The source of ADH is:

A. Adrenal cortex
B. Anterior pituitary
C. Posterior pituitary
D. Hypothalamus

Answer 27

C. Posterior pituitary

Question 28

This hormone is released by increased [K] and [ANG II]. It’s function is to resorb sodium and excrete potassium.

A. ADH
B. ANG I
C. ANG II
D. Aldosterone

Answer 28

D. Aldosterone

Question 29

This hormone increases water and sodium resorbtion. It functions to release aldosterone and constrict efferent arterioles.

A. ADH
B. ANG I
C. ANG II
D. Aldosterone

Answer 29

C. ANG II

Question 30

Binding of this hormone to the V2-R on the DCT promotes increased water reabsorption. What is the hormone and what is its mechanism of action?

A. AGN II; increased Aquaporin-2 in the DCT membrane
B. ADH; Increased aquaporin-2 in the DCT membrane
C. Renin; increased diffusion of water across the renal plasma membrane
D. AGN II: increased diffusion of water across the renal plasma membrane

Answer 30

B. ADH; Increased aquaporin-2 in the DCT membrane