Which organ is primarily responsible for waste removal from the blood?

Which organ is primarily responsible for waste removal from the blood?

• A. Liver
• B. Kidney
• C. Heart
• D. Lungs

Answer: (B)

Waste removal from the blood is handled mainly by the kidneys. They act as the body's filtration system, containing millions of filtering units called nephrons. Blood travels into the kidneys and is filtered; wastes such as urea, excess salts, and other small molecules pass into the forming urine, while useful substances are reabsorbed back into the bloodstream. This process helps regulate fluid balance, electrolyte levels, and pH, keeping the internal environment stable. Other organs have different roles in processing wastes. The liver detoxifies chemicals and metabolizes substances, producing waste products that are often excreted into bile or converted for elimination, but the actual removal of waste from the blood as urine comes primarily from the kidneys. The lungs expel carbon dioxide and some water vapor, a gaseous waste, but they aren’t the main route for removing liquid or solid wastes from the blood. The heart pumps blood through the body but does not remove wastes itself. So the organ most responsible for removing waste from the blood is the kidney.

Waste removal from the blood is handled mainly by the kidneys. They act as the body's filtration system, containing millions of filtering units called nephrons. Blood travels into the kidneys and is filtered; wastes such as urea, excess salts, and other small molecules pass into the forming urine, while useful substances are reabsorbed back into the bloodstream. This process helps regulate fluid balance, electrolyte levels, and pH, keeping the internal environment stable.

Other organs have different roles in processing wastes. The liver detoxifies chemicals and metabolizes substances, producing waste products that are often excreted into bile or converted for elimination, but the actual removal of waste from the blood as urine comes primarily from the kidneys. The lungs expel carbon dioxide and some water vapor, a gaseous waste, but they aren’t the main route for removing liquid or solid wastes from the blood. The heart pumps blood through the body but does not remove wastes itself.

So the organ most responsible for removing waste from the blood is the kidney.