Regulation of Na+ handling

Question 1

Low pressure baroreceptors

Answer 1

Located in the atria and pulmonary vascular bed; increased venous return to the right side of the heart stimulates atrial wall stretch receptors the hypothalamus to decrease renal sympathetic nerve activity

Net result is a loss of sodium and water retention by the kidney and a reduction in ECF volume expansion

Question 2

High pressure baroreceptors

Answer 2

Located in the aortic and carotid bodies

Decreased EABV signals high pressure baroreceptors to signal the hypothalamus, which increases renal sympathetic nerve activity

Net effect is retention of salt and water, increasing volume expansion

Question 3

Juxtaglomerular Apparatus

Answer 3

The main intra-renal baroreceptor

Decreased arterial pressure signals the JXA to release renin which is converted to angiotensin II, which releases aldosterone ultimately leading to Na+ reabsorption

Question 4

Renal Sympathetic nerve

Answer 4

Stimulated by volume contraction; constricts the afferent and efferent arterioles in order to preserve GFR

Also enhances the release of renin from the JGA