Birds circulatory system is characterized by how many heart chambers?

Birds circulatory system is characterized by how many heart chambers?

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

Answer: (A)

Birds have a four-chambered heart, with two atria and two ventricles. This setup keeps oxygenated and deoxygenated blood completely separate, so blood going to the lungs is distinct from blood going to the rest of the body. That full separation supports the high metabolic rate birds need for flight. Other designs aren’t suitable: three-chambered hearts mix blood to some extent and are common in many reptiles, while two-chambered hearts occur in fishes and can’t meet the oxygen demands of active, endothermic animals. A five-chambered arrangement isn’t a standard vertebrate heart design.

Birds have a four-chambered heart, with two atria and two ventricles. This setup keeps oxygenated and deoxygenated blood completely separate, so blood going to the lungs is distinct from blood going to the rest of the body. That full separation supports the high metabolic rate birds need for flight. Other designs aren’t suitable: three-chambered hearts mix blood to some extent and are common in many reptiles, while two-chambered hearts occur in fishes and can’t meet the oxygen demands of active, endothermic animals. A five-chambered arrangement isn’t a standard vertebrate heart design.