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Erythropoiesis—the kidneys will sense a low oxygen tension in the bloodstream and will cause erythropoietin (EPO) secretion. People with kidney failure can lose EPO production and will develop anemia from this.
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Blood pressure regulation—this happens mainly through the regulation of water and sodium balance in the kidneys and in the body. A loss of kidney function can lead to a loss of volume control in the kidneys, which can result in low blood or high blood pressure situations.
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Osmolarity regulation— the kidneys must hold on to protein in order to maintain the osmolarity of the blood system. If protein is lost by damaged kidneys, this can lead to a loss of osmolarity and the potential for leakage of water into the interstitial spaces. This leads to peripheral edema.
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pH Regulation—this involves the maintenance of the pH of the blood and body so as to keep homeostatic mechanisms in place.
URINE COMPOSITION So far, we have learned about the making of urine by the glomeruli and the rest of the renal tissue. While nearly 200 liters of filtrate pass through the glomeruli per day, all but 1-2 liters are made as urine during this time. The urine composition depends on water intake, level of exercise, nutrient intake, environmental temperature, and others. Urine can be fairly clear or dark amber, depending on how concentrated it is. A urinalysis is done to assess the presence or absence of kidney diseases as well as other possible diseases (such as liver disease or diabetes). The color of urine comes mainly from the breakdown of hemoglobin and the production of urochrome, a yellow breakdown pigment. The urine color can also be affected by eating berries, fava beans, or beets, which contain pigmented molecules. Blood in the urine comes from bladder or kidney infections, urinary tract infections or cancers, and sometimes kidney stones. Dehydration will darken the urine and will make it slightly more malodorous. Ammonia comes from the urea in the urine but doesn’t create an odor until the urine has sat outside the
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