Kidneys excrete waste products and excess fluids from the body, maintaining a healthy balance of essential substances in the blood. This process is crucial for overall health.
Key Excretory Functions of the Kidneys
The kidneys perform several vital excretory functions:
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Waste Removal: Kidneys filter blood, removing harmful substances like urea (a byproduct of protein metabolism), creatinine (a product of muscle metabolism), and uric acid (a byproduct of purine metabolism). [Source: Why are the kidneys important? Your kidneys remove wastes and extra fluid from your body.]
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Fluid Balance: They regulate the body's water balance by removing excess water and electrolytes. This prevents dehydration or overhydration. [Source: Why are the kidneys important? Your kidneys also remove acid that is produced by the cells of your body and maintain a healthy balance of water, salts, and minerals—such as sodium, calcium, phosphorus, and potassium—in your blood.]
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Acid-Base Balance: Kidneys help maintain the body's pH balance by excreting excess acids or bases. [Source: Video: Overview of the Role of the Kidneys in Acid-Base Balance ... By adjusting the amounts reabsorbed and secreted, they balance the bloodstream's pH.]
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Electrolyte Regulation: Kidneys regulate levels of essential electrolytes, including sodium, potassium, calcium, and phosphorus, ensuring their balance in the bloodstream. [Source: Why are the kidneys important? Your kidneys also remove acid that is produced by the cells of your body and maintain a healthy balance of water, salts, and minerals—such as sodium, calcium, phosphorus, and potassium—in your blood.]
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Hormone Production: Although not strictly excretion, the kidneys also produce hormones like erythropoietin (stimulates red blood cell production) and renin (regulates blood pressure).
The Process of Excretion
The kidneys filter blood through tiny units called nephrons. Waste products are removed from the blood and formed into urine. This urine is then stored in the bladder until it is excreted from the body. [Source: a What job is done by the kidneys ? b What do kidneys excrete ? c ... The kidneys remove the poisonous substances like urea, other waste salts and excess water from the blood in the form of yellowish liquid called urine.]
What is excreted specifically?
The kidneys excrete a complex mixture of substances, including:
- Urea: The primary nitrogenous waste product.
- Creatinine: A waste product from muscle metabolism.
- Uric acid: A waste product from purine metabolism.
- Excess water: To maintain fluid balance.
- Excess electrolytes: Such as sodium, potassium, and others.
- Excess acids or bases: To maintain pH balance.
The specific composition of urine reflects the body's overall metabolic state and fluid balance. [Source: Renal Excretion - an overview | ScienceDirect Topics Renal excretion involves three processes: glomerular filtration, tubular secretion, and/or tubular reabsorption]
