How many heart chambers do mammals have?

How many heart chambers do mammals have?

• A. Two
• B. Three
• C. Four
• D. Five

Answer: (C)

Mammals have four chambers in the heart: two atria and two ventricles. This four-chambered design keeps oxygen-poor blood and oxygen-rich blood completely separate, which is essential for the high metabolism of mammals. Blood returns from the body into the right atrium, moves to the right ventricle and is pumped to the lungs for oxygenation. Oxygenated blood flows from the lungs into the left atrium, then to the left ventricle to be circulated to the body. The full separation of the pulmonary and systemic circuits allows efficient oxygen delivery to tissues, supporting warm-blooded activity. Some other vertebrates have fewer chambers with some mixing, but mammals specifically have four.

Mammals have four chambers in the heart: two atria and two ventricles. This four-chambered design keeps oxygen-poor blood and oxygen-rich blood completely separate, which is essential for the high metabolism of mammals. Blood returns from the body into the right atrium, moves to the right ventricle and is pumped to the lungs for oxygenation. Oxygenated blood flows from the lungs into the left atrium, then to the left ventricle to be circulated to the body. The full separation of the pulmonary and systemic circuits allows efficient oxygen delivery to tissues, supporting warm-blooded activity. Some other vertebrates have fewer chambers with some mixing, but mammals specifically have four.