excertion III 2012 final

The collecting duct cells allowing water to flow down

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Unformatted text preview: the incorporation of aquaporin into the apical membrane of the collecting duct cells • Allowing water to flow down its osmotic gradient Vasopressin response time is relatively short Monday, April 30, 12 Vasopressin is released in response to high osmotic pressure of the extracellular fluids and low blood pressure While hypotonicity and high blood pressure triggers a decrease in the vasopressin release Monday, April 30, 12 The Renin-Angiotensin-Aldosterone Pathway • Aldosterone released from the adrenal cortex • Also called mineralcorticoid due to its role in the regulation of K+ and Na+ levels • Aldosterone is released in responses to low arterial blood pressure Monday, April 30, 12 • Specialized cells in the kidney (juxtaglomerular cells) are sensitive to blood pressure - The juxtaglomerular cells release Renin in response to low blood pressure • Renin converts Angiotensinogogen (a preprohormone) to Angiotensin I (a prohormone) • Angiotensin Converting Enzyme (ACE) converts Angiotensin I to the active Angiotensin II Monday, April 30, 12 Angiotensin II promotes an increase in arterial blood pressure by •Promoting Thirst •Stimulating constriction of arterioles •Stimulating vasopressin release •Promoting salt appetite •Promoting Aldosterone Release Enhanced Salt Appetite Monday, April 30, 12 • Aldosterone targets the cells of the late distal tubule and the collecting duct – Aldosterone increases the cell’s ability to resorb Na+ and to stimulates the release of K+ • Stimulates synthesis Na+-K+-ATPase pumps and of Na+ and K+ channels Pump creates a steep Na+ & K+ Gradients Monday, April 30, 12 • Together Vasopressin and Aldosterone work to Maintain Na+ and water balance Monday,...
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This note was uploaded on 10/10/2013 for the course BIO 1440 taught by Professor Booker during the Spring '13 term at Cornell.

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