Primary Hormones that Influence Renal Function

Question 1

Antidiuretic Hormone (ADH)

Answer 1

Primary determinant of plasma osmolarity through the control of water reabsorption or secretion in the distal nephron. 1.) Increases the permeability of cordical and medullary collecting ducts to water 2.) Increases the permeability of the collecting duct to urea 3.) Stimulates Na-K-2Cl pump in thick ascending limb of the loop of henle 4.) Stimulates production of renal prostaglandins

Question 2

Renin-Angiotensin II System - Role of Angiotensin II

Answer 2

Primary “low blood volume (pressure) response system” Angiotensin II 1.) causes vasoconstriction of both efferent and afferent (lesser extent) arterioles to limit the fall in GFR relative to renal blood flow in low volume states. 2.) Stimulates aldoserone release. 3.) Stimulates synthesis of vasodilatory prostaglandins 4.) Inhibits renin release 5.) Increases sodium and water reabsorption in the proximal tubule

Question 3

Aldosterone

Answer 3

1.) Increases Na and Cl (and watera) reabsorption in the cortical and medullary collecting ducts - increases the isoosmotic reabsorption of water 2.) Increases K+ and H+ secretion in the collecting ducts 3.) Primary derminant of urinary K excretion (balance of reabsorption and secretion)

Question 4

Atrial natriuretic peptide (ANP) and Brain (B-type) Natriuretic peptide (BNP)

Answer 4

Part of the low pressure, high blood volume response system. 1.) renal vasodilation and increases both renal blood flow and GFR 2.) Increase Na excretion (natiuresis) and water excretion (diuresis)

Question 5

Urodilatin

Answer 5

An ANP like hormone produced within the nephron in response to hypervolemia. Increases Na excretion (natriuresis) and water excretion (diuresis)

Question 6

Prostaglandins

Answer 6

PGE2 and prostacyclin are vasodilators that modilate renal blood flow by antagonizing vasoconstrictor effects of sympathetic stimulation and angiotensin II (important to prevent renal ischemia)

Question 7

Parathyroid Hormone

Answer 7

released in response to low plasma calcium levels . 1.) Activates calcitrol 2.) increases the active reabsorption of Ca2+ in the distal tubule 3.) decreases proximal tubule reabsorption of phosphate

Question 8

Calcitrol

Answer 8

Most active form of Vitamin D3. 1.) Increases Ca+ and phosphate reabsorption 2.) Negative feedback on parathyroid hormone release

Question 9

Catecholamines (norepinephrine and epinephrine)

Answer 9

1.) Vasoconstriction of afferent and efferent arterioles (a1) and decrease RBF and GFR 2.) stimulates tubuar (proximal loop of henle) Na reabsorption 3.) Activates the renin-angiotensin system via B1 receptors in JGA of afferent arteriole

Question 10

Kinins

Answer 10

Vasodilators that appear to antagonize neurohumoral vasoconstriction sililar to prostaglandins . May play a role in Na and water handling in the ocllecting duct by antagonizing ADH-mediated water reabsorption