Which organ is primarily responsible for copper excretion from the body?

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

Answer: (A)

Copper balance is controlled mainly by the liver, which excretes excess copper into bile for elimination in feces. After absorption, copper is taken to the liver, where it’s safely stored or bound to proteins like metallothionein and ceruloplasmin. When there’s more copper than these stores can handle, the liver uses a transporter to move copper into bile, making biliary excretion the primary elimination pathway. The kidneys do remove some copper in urine, but this is a minor route, and the lungs and skin don’t contribute meaningfully to copper excretion.