Term
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Definition
The medulla is much less hyperosmotic because:
1. urea is lot in the urine, eventually its concentration drops in the inner medulla
2. less urea makes the countercurrent multiplication less efficient: also less Na in interstitium |
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Term
| Central Diabetes Insipidus |
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Definition
| Lack of ADH. Large volume of dilute urine (up to 20L/day). May lead to hypternatremia, if H2O isnt available. Pts will drink a lot. Can be treated with ADH. |
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Term
| Nephrogenic Diabetes Insipidus |
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Definition
| Congenital: Lack of ADH receptor or aquaporin. Has acquired forms, side effect of some medications (Lithium). Treatment: (1) does not respond to ADH (2) Adequate hydration (3) Sodium restriction to prevent hypernatremia |
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Term
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Definition
| Syndrome of inappropriate ADH secretion >> H20 retention. Causes (1) hyponatremia (if develops quickly: cerebral edema >> irritability, confusion, coma) (2) Concentrated urine |
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Term
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Definition
| Osmotic diuresis. Glucose exceeds tubular threshold >> appears in urine. Osmotically active >> retains water in tubules >> large volume of urine. Retained water dilutes salts in tubules >> decreased gradient for reabsorption >> salt (Na and K) loss in urine. Severe dehydration |
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Term
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Definition
| Primary hyperaldosteronism: Increased Na+ reabsorption. Plasma Na+ is not necessarily high. Increased volume>> hypertension. Hypokalemia. Alkalosis (aldo also stimulates H+ secretion of intercalated cells). Renin (Ang 2) levels are low. |
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Term
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Definition
| 2ndary hyperaldosteronism. Renin (Ang II) levels are high. Symptoms are similar to primary hyperaldosteronism. |
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Term
| Reabsorption of Amino Acids |
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Definition
| Amino Acids –reabsorbed by a variety of mechanisms, usually involving combinations of facilitated diffusion and secondary active transporters at basolateral and apical membranes. Complete by end of proximal tubule |
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Term
| Reabsorption of Carboxylates |
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Definition
| reabsorbed by Na+ coupled cotransporters. Complete by end of proximal tubule |
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Term
| Reabsorption of Oligopeptides |
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Definition
| reabsorbed by H+ coupled transport if they are shorter, or by degradation into constituent amino acids if they are longer. Complete by end of proximal tubule. |
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Term
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Definition
| the small amounts of protein that manage to escape into the filtrate are reabsorbed by endocytosis, but about 1% of the filtered load is excreted (remember that normal protein levels in the urine should be <100 mg). Complete by end of proximal tubule |
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Term
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Definition
Hyperkalemia: >5mM in ECF – cells are depolarized, leading to arrythmias and death.
Hypokalemia: <3.5mM in ECF – cells are hyperpolarized, leading to muscle weakness and constipation. |
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