Deck 53: Tubular Reabsorption and Secretion

Question 1

The filtered load of solute X is calculated as

A) Q U U X / PX
B) (TFX/ PX)/(TFinulin /Pinulin)
C) C B / CP
D) GFR © P
E) TFX / PX

Answer 1

D

Question 2

The cle ar an ce of in ulin

A) depends linearly on the plasma [inulin]
B) decreases with Increases in plasma [inulin]
C) Increases with Increases in plasma [inulin]
D) is independent of plasma [inulin]
E) saturates with Increasing [inulin]

Answer 2

D

Question 3

[TF /P] inulin at the end of the proximal tubule is 3 and at the same place [TF/P]Na = 1. You conclude from this that

A) 2/3 o f the Na is re-a bs orb ed in th e pr ox im al tu bu le
B) 1/3 of t he wa ter is re -a bs or be d in the pro xim al tu bu le
C) The fluid reabsorbed in the proximal tubule is isoosmolar with plasma
D) Inulin is freely filtered but not reabsorbed or secreted
E) Both A and C are true

Answer 3

A

Question 4

"Sp lay" refe rs to

A) The appearance of material in the urine before the filtered load exceeds the transport maximum
B) Ne phro n he terog ene ity
C) Saturation kinetics
D) Carrier transport mechanisms
E) The dependence of clearance on plasma concentration

Question 5

The T m for a s ec re ted m ate ria l, X , is

A) about 120 mL m in -1
B) its m axim um exc retor y rate
C) 8
D) its maximum secretory rate
E) its m axim um filtration rate

Question 6

The cle ar an ce of in ulin is 1 00 m L m in-1 in a pa tient. His plasm a co nce ntration of so lute X is 0.2 mg% and a 4-hour urine specimen was 240 m L, with a urinary concentration of solute X of 60 mg% . From this information you can conclude

A) Substance X is not freely filtered
B) Substance X is reabsorbed
C) Substance X is secreted
D) Substance X is both filtered and secreted
E) Substance X is both freely filtered and reabsorbed

Question 7

The filte re d lo ad of g luc os e p er da y

A) Is more than the total glucose in all of the body fluids
B) Is a small fraction of the total glucose in plasma
C) Is about the same as the amount of glucose contained in plasma
D) Is more than the amount of glucose in all of the carbohydrate stores in the body
E) Accounts for the glucose in the urine

Question 8

The greatest part of water and nutrient reabsorption occurs in the

A) Bo wm an 's c ap su le
B) dis tal tu bu le
C) Lo op of H en le
D) collecting duct
E) pro xim al tu bu le

Question 9

Am ino acids are

A) Reabsorbed by a combination of active and passive transport mechanisms in the pro xim al tu bu le
B) R ea bs or be d p as siv ely in the pro xim al tu bu le
C) Secreted by a combination of active and passive transport mechanisms in the proximal tub ule
D) Se cr ete d p as siv ely in the pro xim al tu bu le
E) Reabsorbed throughout the length of the nephron

Question 10

Glucose reabsorption

A) invo lves a pical S GL T an d ba solate ral GL UT 2 tran spo rters
B) involves apical GLUT 2 and bas olateral SGLT transporters
C) involves apical Na-glucose co untertransport and ba solateral GLUT 2 transporters
D) involves facilitated diffusion at both apical and basolateral mem branes
E) obeys diffusion kinetics

Question 11

The plasma concentration at which glucose first appears in the urine is called the

A) Transport maxim um for glucose
B) Splay
C) The renal threshold for glucose
D) The clearance of glucose
E) The effective renal plasma flow

Question 12

The filte re d lo ad of la rg e p ro tein s is

A) Large because the proteins are large
B) Large because the GFR is so large
C) Sm all because the proteins are small, despite the descriptor "large"
D) Sm all b ec au se the pla sm a c on ce ntr atio n o f pr ote in is sm all
E) Sm all be cau se th e sie vin g co effic ient is sm all

Question 13

At t he n e nd of t he pro xim al tu bu le, [T F / P ] fo r glu co se is n or m ally

A) 1 / 3
B) 2 /3
C) 1
D) 0
E) Indeterminate, depending on the fraction of water reabsorbed

Question 14

Glucose reabsorption

A) Occurs throughout the nephron
B) Oc cu rs o nly in the pro xim al tu bu le
C) Normally is limited to the proximal tubule but can occur in the distal nephron when glucose load is high
D) O cc ur s in the pro xim al tu bu le a nd dis tal tu bu le
E) Is entirely passive

Question 15

The kidney plays a major role in the regulation of plasma concentrations of

A) Glucose
B) Am ino acids
C) Pho spha te
D) Pr ote in
E) Lac tate

Question 16

The gra ph o f the filtere d load of inu lin plotted aga inst the plasm a co nce ntration of inu lin is linear. T his is b ec au se inu lin is

A) Freely filtered but not reabsorbed or secreted
B) Freely filtered and reabsorbed
C) Freely filtered and also secreted
D) Not filtered, reabsorbed or secreted
E) Avidly destroyed by the kidney

Question 17

Creatinine clearance is a good approximation to the GFR because creatinine

A) Is made in the body
B) Is free ly filtere d an d n ot re ab so rbe d an d se cret ed on ly a little
C) Is avidly secreted
D) Concentration in plasma is relatively constant
E) Concentration in plasma is inversely related to the GFR

Question 18

If the G FR is halve d, you w ould exp ect

A) Creatinine clearance to be unchanged
B) Creatinine clearance to be approximately doubled
C) Plasma creatinine concentration to be approximately halved
D) Plasma creatinine concentration to be approximately doubled
E) Creatinine excretion to be approximately halved

Question 19

Splay in renal titration curves is caused by

A) Saturation kinetics
B) Passive transport mechanisms
C) Nep hron heterog eneity
D) Counter-current flow
E) Both A and C are true

Question 20

G luc os e is fre ely filt er ed , bu t no rm ally th e u rin ar y co nc en tra tion of g luc os e is zer o. T his is because

A) Glucose is metabolized by the kidney
B) Glucose is normally completely reabsorbed
C) Glucose is avidly secreted
D) Glucose reabsorption exceeds filtration
E) Glucose secretion augments filtration

Question 21

At t he en d o f th e p ro xim al tu bu le, [T F / P ] fo r am ino ac ids is n or m ally

A) 1 / 3
B) 2 /3
C) 1
D) 0
E) Indeterminate, depending on the fraction of water reabsorbed

Question 22

The rela tive ly sm all fr ac tion of p ro tein s f ilter ed by th e g lom er ulu s is

A) D eg ra de d b y the pro xim al tu bu le
B) Passed unchanged into the urine
C) R ea bs or be d b y en do cyto sis
D) Stuck together in the final urine
E) Both A and C are true

Question 23

HCO - rea bs or ptio n in the pro xim al tu bu le

A) Requires acid secretion at the luminal membrane - -
B) Requires a HCO 3 - Cl exchanger at the luminal mem brane - -
C) Requires a HCO 3 - Cl exchanger at the basolateral membrane
D) Requires carbonic anhydrase in the plasma
E) Requires Na+ secretion