Chapter 7 - Control of sodium and water excretion

Question 1

3 ways that kidney influence the CV system

Answer 1

Blood volume: RBC production
Blood volume: ECF volume (Na, H2O in plasma)
Blood pressure: TPR (renin-AG)

Question 2

3 kinds of baroreceptors

Answer 2

1. Arterial baroreceptors (carotid artery, aortic body): sense pressure by beat-to-beat basis
2. Cardiopulmonary baroreceptor: sense pressure in regions of vascular tree where pressure are much lower than the arteries, de facto blood volume detectors
3. Neural baroreceptors (medulla oblongata, lower region of brainstem) = vasomotor center

Question 3

How arterial baroreceptors regulate BP?

Answer 3

Arterial baroreceptors: tonic inhibition- brake on sympathetic drive (increase in ABP, more inhibition from arterial baroreceptor, less sympathetic drive to periphery, decrease in ABP, decreased inhibition, more sympathetic drive)

Question 4

Effect of norepinephrine to RBF and GFR-

Answer 4

decrease (vasoconstriction of afferent and effect arteriole, more constriction of afferent arterioles)

Question 5

Effect of norepinephrine on proximal tubular epithelial cell

Answer 5

sodium-hydrogen anti porter in the apical membrane and Na-K-ATPase in the basolateral membrane: reduce sodium excretion

Question 6

Effect of AG2 to RBF, GFR

Answer 6

(decreased): vasoconstrictor cortical and medullary vessel in the kidneys
AG2 stimulate sodium reabsorption in both proximal tubule and distal nephrite

Question 7

How AG2 stimulate sodium reabsorption

Answer 7

(same as Norepi)

1. Proximal tubule: NHE3 Na-H antioprtoer in apical membrane, Na-K-ATPase in the basolateral membrane
2. Distal tubule, collecting duct: Na-Cl anti porter, Na channel (ENaC) that reabsorb sodium

Question 8

How Aldosterone work in the distal tubule?

Answer 8

Freely cross principal cell membrane, combine to mineralocorticoid receptor, increase activity of luminal membrane sodium channel (ENaC) and basolateral membrane Na-K-ATPase pumps

Question 9

3 control of renin secretion

Answer 9

1. Adrenergic (beta 1 in the granular cell, cAMP mediated pathway)
2. Pressure in the afferent arteriole (granular cell- baroreceptors)
3. Macula densa

Question 10

Name of precursor of dopamine

Answer 10

1-DOPA

Question 11

T/F: inhibit sodium reabsorption

Answer 11

True: 2 actions of it: 1) retraction of NHE anti porter and Na-K-ATPase pump into intracellular vesicle, 2) reduce the expression of AG2 receptors, thereby decrease the ability of AG2

Question 12

T/F: body consider volume more importantly than osmolality

Answer 12

Answer is true or false.
When change in volume and osmolality are small to moderate: osmoreceptor predominates over baroreceptors
When plasma volume is dangerously reduced, volume takes over the osmolality