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aldosterone action in the nephron. recall our nephron diagram. need to add a new structure. juxtaglomerular cells JUX-ta-glo-MAR-you-lar. sense blood pressure like a collar wrap around afferent arteriole (the arteriole leading to the glomerulus). normal blood pressure.
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recall our nephron diagram... need to add a new structure...
juxtaglomerular cells JUX-ta-glo-MAR-you-lar • sense blood pressure • like a collar • wrap around afferent arteriole • (the arteriole leading to the glomerulus)
normal blood pressure low blood pressure high blood pressure • glomerulus works on PRESSURE • if blood pressure is too low, filtration won’t happen fast enough • urea will stay in the blood • blood will become toxic
blood pressure too low JG cells release renin renin activates angiotensin Na+ angiotensin calls aldosterone (from adrenal gland) aldosterone causes increased Na+ reabsorption blood volume and blood pressure increase blood gets “saltier” blood absorbs MORE WATER by osmosis
angiotensin adrenal gland renin aldosterone Na+ water enters blood by osmosis
JG cells sense blood pressure (stretch receptors). if BP is too low... • JG cells secrete renin • renin activates angiotensin • angiotensin calls aldosterone (from adrenal cortex) • aldosterone causes increased reabsorption of sodium in the DCT • increased Na+ causes increased osmosis of water into bloodstream • blood volume increases • blood pressure increases • GFR increases
blood pressure too low JG cells release renin renin activates angiotensin Na+ angiotensin calls aldosterone (from adrenal gland) aldosterone causes increased Na+ reabsorption blood volume and blood pressure increase blood gets “saltier” blood absorbs MORE WATER by osmosis
normal blood pressure low blood pressure high blood pressure • glomerulus works on PRESSURE • if blood pressure is too low, filtration won’t happen fast enough • urea will stay in the blood • blood will become toxic