Keef Lecture 5

Question 1

About how much of the filtered load of urea is excreted in the urine?

Answer 1

40%

Question 2

What is the greatest stimulus of ADH release?

Answer 2

An increase in osmolarity

Question 3

Is the ADH receptor intracellular or extracellular?

Answer 3

Extracellular

Question 4

Discuss what happens when ADH binds to its extracellular receptor.

Answer 4

ADH binds and activates Gs, which increased cAMP, and activates PKA. This leads to movement of water pores to the apical membrane, and increased water reabsorption.

Question 5

Discuss what occurs with ADH in neurogenic diabetes insipidus.

Answer 5

Lack of synthesis of ADH. Can be corrected by administration of ADH.

Question 6

Discuss what occurs with ADH in nephrogenic diabetes insipidus.

Answer 6

Lack of kidney response to ADH. So, even if you administer ADH, urine flow rate will be unchanged.

Question 7

What is SIADH?

Answer 7

Too much ADH release

Question 8

A condition in which urine flow is greater than normal (V > 1ml/min)

Answer 8

Diuresis; produces hypotonic urine

Question 9

A condition in which urine flow is less than normal (V < 0.5ml/min)

Answer 9

Antidiuresis

Question 10

What is osmotic diuresis?

Answer 10

Too many particles in the tubule, so increased water retention, and increased urine flow. Ex: diabetes mellitus

Question 11

During diuresis, does the urine have a high or low osmolarity?

Answer 11

Low! Hypotonic urine

Question 12

During antidiuresis, does the urine have a high or low osmolarity?

Answer 12

High! Hypertonic urine

Question 13

Is clearance of urea greater during diuresis or antidiuresis?

Answer 13

Diuresis