The Digestive System

The Digestive System - The Digestive System Regulation of...

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The Digestive System Regulation of Extracellular Fluid Composition The total amount of water and electrolytes in the body does not change unless the person is growing, gaining weight, or losing weight. Thirst o The sensation of thirst increases if extracellular fluid becomes more concentrated or if blood pressure decreases. Ions o Sodium ions are one of the dominant extracellular ions. Aldosterone increases sodium reabsorption from the filtrate. ADH increases water reabsorption from the nephron, and atrial natriuretic hormone increases sodium loss in the urine. o Aldosterone increases potassium secretion in the urine. Increased blood levels of potassium stimulate, and decreased blood levels of potassium inhibit, aldosterone secretion. o Parathyroid hormone secreted from the parathyroid glands increases extracellular calcium levels by causing bone resorption and increased calcium uptake in the kidney and small intestine. Parathyroid hormone increases vitamin D synthesis. Calcitonin, secreted by the thyroid gland,
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This note was uploaded on 12/04/2011 for the course ANTHRO 2000 taught by Professor Monicaoyola during the Fall '10 term at Broward College.

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