Water balance

Question 1

What percentage of water enters the Collecting duct?

Answer 1

15% around 100mosm

Question 2

What 2 types of cell is present?

Answer 2

Principle and Intercalated cells

Question 3

What are Priniciple cells involved with?

Answer 3

Water and salt regulation

Question 4

What are Intercalated cells involved with?

Answer 4

Acid-base balance.

Question 5

ADH has what effect?

Answer 5

Cause a 50 fold increase in water permeability.

Question 6

What happens when ADH binds to V2R on basolateral surface?

Answer 6

Signal via cAMP to phosphorylate AQP2 which is exocytosed to surface.

Question 7

What are some modulators of ADH?

Answer 7

Receptors downregulation by internalisation, modulating adenylate cyclas (prostaglandins, a2 adrenergic), Cytosoloic Ca, Altered presence of AQP2

Question 8

What causes secretion of Vasopressin?

Answer 8

Osmolarity

Question 9

What factors increase secretion of vasopressin?

Answer 9

Nausea, Hypoglycaemia, Hypoxia, Hypercapia, Angiotenisin, Stress