Lect 4 - Block 3 - Tubular Function, Reabsorption, Secretion

Question 1

5 things, in order, that something being reabsorbed in the trans-cellular pathway has to travel/diffuse through

Answer 1

Apical surface of epithelial cell,
diffuse through cell,
cross basolateral surface of epithelial cell,
diffuse through renal interstitial fluid,
Enter peritubular capillary

Question 2

Lumen

Answer 2

Contains filtrate, “outside” of the body, apical surface of cells

Question 3

Serosa

Answer 3

Interstitial fluid, “blood side”, basolateral surface

Question 4

The Na/K-ATPase is found on the ______ surface of tubular epithelial cells

Answer 4

Basolateral surface

Question 5

Microvilli are found on the _______ surface of tubular epithelial cells

Answer 5

Apical surface

Question 6

All of the glucose that is filtered is normally reabsorbed by the ____________part of the nephron

Answer 6

Proximal tubule

Question 7

Two filtrates that are fully reabsorbed in a normal kidney

Answer 7

HCO3 and glucose

Question 8

Bicarbonate (is/isn’t) excreted
Urine pH is (greater/lesser) than plasma pH

Answer 8

Bicarbonate isn’t excreted
Urine pH is more acidic than plasma

Question 9

Amount of _______ in urine is the same as the amount filtered into Bowman’s capsule. This is why it can be used to measure GFR

Answer 9

Creatinine

Question 10

4 things transported proximal tubule
4 things that diffuse in proximal tubule

Answer 10

Transport: Na, bicarbonate, glucose, amino acids

Diffusion: water, urea, Cl, K

Question 11

Presence of glucose in urine means that the plasma glucose has been high in here past _____ hours

Answer 11

6 hours, or time since last urination

Question 12

Glucose and amino acids are reabsorbed by _______ transport in the apical surface, along with ______

Once in the cell, glucose and amino acids move to the interstitial space by __________

Answer 12

Secondary active transport, sodium

Facilitated diffusion

Question 13

Only movement of molecules or ions in proximal tubule that requires energy

Answer 13

Na/K-ATPase

Question 14

Proximal tubule has hydrogen-sodium anti porters on the ______ surface (_______ transport.) This helps to move bicarbonate.

The hydrogen binds with bicarbonate in a reaction catalyzed by _______ and allows ____ to diffuse across the membrane. This then reacts with more enzyme.

The product, ______, is then transported into the ISF via _______

Answer 14

Apical, Secondary active transport

Carbonic anhydrase, co2

Bicarbonate-chloride antiport (basolateral surface)

Question 15

Glucose show up in urine when blood glucose filtered load is _____-_____mg/min

Normal is _____

At _____ it’s a linear relationship (difference in nephron handling of glucose no longer a factor; all are saturated)

Answer 15

250-300

125

400

Question 16

The reabsorption of ________ in the early proximal tubule is the first step in the series of proximal tubule reabsorption processes. It sets up the osmotic gradient, which drives the concentration gradient for all other tubular compounds.

Answer 16

Sodium bicarbonate

Question 17

Water, K, Cl move via _________ pathway

Answer 17

Paracellular pathway

Question 18

Carbonic anhydrase can be inhibited by ________

This decreases movement of ____,_____,_____,_____
There is no change in movement of ________

Answer 18

Acetazolamide (diuretic)

Na, Cl, K, water decrease
Glucose remains the same

Question 19

In the proximal tubule _/_ of salt and water are reabsorbed.

All ____ and ____ is reabsorbed

The filtrate is _______ from the beginning to the end of the proximal tubule

Answer 19

2/3

Glucose, amino acids

Isotonic

Question 20

Certain ______ and ______ can be SECRETED in the proximal tubule

Answer 20

Organic acids and bases

Question 21

The concentration of Inulin at the end of the proximal tubule is ___ times the concentration at Bowman’s capsule

Answer 21

3

Question 22

A fractional excretion of Na+ of greater than _____% indicates tubular damage

Answer 22

2%