Regulation of Sodium and Water Excretion I/II Flashcards Preview

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Flashcards in Regulation of Sodium and Water Excretion I/II Deck (16):
1

Formula for extracellular fluid volume:

ECF volume= (2xECF Na content)/ECF osmolarity

2

What are the four feedback mechanisms?

1.) Renin-angiotensin-aldosterone pathway
2.) Sympathetic nerve activity pathway
3.) Arginine vasopressin pathway
4.) Atrial natriuretic peptide pathway

3

What is the main reason for the four feedback mechanisms?

Control of an effective circulation volume

4

Where is renin released?

Lumen of the afferent arterioles

5

Two mechanisms of renin secretion?

Renal sympathetic nerves (beta 1)
Low afferent arteriole pressure

6

What does Angiotensin II cause in the kidney?

Inhibit renin production
Sodium retention

7

What does angiotensin cause the secretion of?

Aldosterone

8

What does aldosterone cause?

Increase in genetic expression of apical membrane Na+ channels and basolateral Na/K ATPase

9

What are the critical events that the sympathetic nervous system has on the kidney?

Renin-angiotensin-aldosterone cascade

10

What are two mechanisms AVP is released?

1.) Low pressure triggers baroreceptors in the atria send signals to the hypothalamus
2.) Osmoreceptors in the hypothalamus monitoring circulating blood (increase in osmolarity causes a increase in water resorption)

11

What is the normal blood osmolality?

300 mOsm

12

What does ANP do?

Dilates afferent arterioles
Inhibits renin release
Inhibits A2 actions
Inhibits medullary collecting duct of Na+ resorption

13

What is the main stimulus for release of ANP?

Distension of the atrial walls

14

What is pressure natriuresis and diuresis?

Increased pressure in renal artery causes and increase in Na+ excretion causing water to follow and diuresis

15

Formula for urine water excretion?

Urine water excretion= urine solute secretion/urine osmolality

16

Mechanism AVP/ADH works on kidney?

Binds to V2 receptors in the principal cells of the collecting duct increasing cAMP causing increased genomic expression of aquaporin 2 and an increase of aquaporin 2 transport to the cell membrane