Mangiarua - Na Water Transport

Question 1

the sodium movement across the luminal membrane is alway ____

Answer 1

Downhill

Question 2

The major site for reabsorption of water and salt?

Answer 2

The proximal tubule

Question 3

What happens to reabsorption when there are changes in GFR?

Answer 3

The proximal tubule reasorbs a constant FRaction of filtered fluid. But overall load decreases

Question 4

Increased urine flow that is due to extra amount of non-reabsorbed solute within the tubular lumen

Can be caused by mannitol

Occurs in severe diabetes

Answer 4

Osmotic diuresis

Question 5

Location in the nephron which reabsorbs approximately 25% of the filtered sodium and chloride and roughly 15% of the filtered water

Answer 5

Loop of Henle

Question 6

Mechanism of action for furosemide and betemanide ?

Answer 6

Inhibition of the Na-K-2Cl symptorters in the thick ascending limb of the loop of Henle

Question 7

What percentage of filtered sodium and chloride ions reach the distal tubule ?

Answer 7

10%

Question 8

What percentage of filtered water reaches the distal tubule

Answer 8

20%

Question 9

What is the target for inhibition of thiazide diuretics?

Answer 9

NaCl symporter in the distal convoluted tubule

Question 10

caused by mutations in the gene that codes for the epithelial sodium channel (ENaC) in the principal cells of the collecting duct system inducing excess Na+ reabsorption. It is characterized by early, and severe hypertension associated with low plasma renin activity, metabolic alkalosis due to hypokalemia, and hypoaldosteronism.

Answer 10

Liddle’s Syndrome

Question 11

caused by mutations in the gene that codes for the Na-Cl cotransporter in the distal tubule. It is characterized by increased excretion of Na+, Mg2+, Cl-, and K+.

Answer 11

Gitelman’s Syndrome

Question 12

caused by mutations of genes encoding proteins that transport ions in the thick ascending limb of the nephron, including the Na-K-2Cl cotransporter, the K+ channel, and the Cl- channel. It is characterized by very large urinary losses of NaCl, hypokalemia. Ca2+ and Mg2+ wasting may also occur.

Answer 12

Bartter’s Syndrome

Question 13

The minimal amount of water that we must excrete each day in order to dissolve the solutes that our body must excrete

Answer 13

Obligatory water loss

0.43L/day

Question 14

The function of the loop countercurrent multiplier system is to ?

Answer 14

Increase the osmotic concentration of the medullary interstitium

Question 15

The descending limb of the loop of henle reabasorbs _____

Answer 15

Water

Question 16

The ascending limb of the loop of Henle reabsorbs _____

Answer 16

Na

Cl

Question 17

In antidiuresis, there is a _____ osmolarity of the medulla and papillae that are due to urea reabsorbed between the medullary collecting duct and ascending loop of henle

Answer 17

High

40-50%

Question 18

In diuresis, there is a ______ permeability of the medullary collecting duct

Answer 18

Low

Only 10% of interstital osmolarity is due to urea

Question 19

“Water free of solutes” is generated in the _____

Answer 19

Ascending limb of the loop of henle

Question 20

Way to quantify the rate of excretion of total solute

Answer 20

Osmolal clearance

Question 21

Compares the rate of solute excretion w/ the rate of water excretion

Answer 21

Free water clearance

Question 22

Free water clearance > 0 when ….

Answer 22

Uosm is less than Posm

Urine is more dilute
Free water is being lost
You are concentrating the plasm

Question 23

Hydropenia

Answer 23

Fluid restriction

Question 24

Regardless of availability of fluid, a person must excrete ate least ______ mOsm/min

Answer 24

0.5-1.0

Question 25

Urine flow that is greater than normal

In excess of 1mL/min in adult human

Answer 25

Diuresis

Question 26

Increased urine flow that is due to extra amount of non-reabsorbed solute within the tubular lumen

(Can be caused by mannitol)

Answer 26

Osmotic diuresis

Question 27

Increased urine flow due to decreased reabsorption of “free” water

Occurs in persons who have drunk a large amount of dilute fluid

Also occurs in patients w/ diabetes insipidus

Answer 27

Water diuresis

Question 28

Urine flow that is less than normal, usually below 0.5 mL / min in adult human

Answer 28

Antidiuresis