The Kidneys
Absorption: The kidney's do the lions share of the work in the excretory system. The kidneys filter the blood for wastes. They do this by diverting the blood flow from an artery and flows it into a tiny network of capillaries called nephrons. While moving through the nephron the blood is under high pressure. This pressure helps excess water, salt, glucose, amino acids, urea, vitamins, and ions into the nephron for filtration. It filters out the wastes and lets the glucose, amino acids, vitamins, and ions reabsorb into the red blood cells.
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The water reabsorption depends on the water level in the body. If the water level is low, then water is reabsorbed very quickly. However, if there is a high amount of water in the body, less water is absorbed. The wastes, some water included, are then filtered out then travel down the ureter for storage in the urinary bladder. They then exit the body as urine.
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