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Aldosterone
Source: Adrenal Cortex
Target and Effect: causes Na+ reabsorption and K+ secretion by increasing the synthesis of basolateral Na+/K+ ATPases in the distal nephron. End result: increased serum [Na+], increased blood volume (through action of ADH) and thus increased blood pressure
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ADH
Source: Posterior Pituitary
- Target and Effect: ADH is secreted when plasma volume is too low, blood pressure is too low, or plasma osmolarity is too high. It causes water reabsorption by causing epithelial cells of the distal nephron to become permeable to water, which allows water to flow out of the filtrate into the medullary interstitium. Vasas recta return this water to the bloodstream. The result is more concentrated urine, and more dilute blood.
- ADH and aldosterone work together to increase blood pressure: first, aldoesterone causes sodium reabsorption, which results in increased plasma osmolarity; this causes ADH to be secreted, which results in increased water reabsorption and thus increased plasma volume
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Calcitonin
Source: C cells (located in the thyroid gland but do not secrete thyroid hormone)
- Target and Effect: C cells secrete calcitonin when the serum [Ca2+] is too high.
- Calcitonin causes [Ca2+] to be removed fromt eh blood by 1) deposition in bone, 2) reduced absorption by the gut, and 3) excretion in urine
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Parathomone
Source: parathyroid
Effect: opposite calcitonin
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EPO (erythropoeitin)
Source: Kidney
Effect: causes increased synthesis of RBC in the bone marrow. It is released when blood oxygen content falls.
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