Amphibia circulatory system is which?

Amphibia circulatory system is which?

• A. Two chambered heart
• B. Three chambered heart
• C. Four chambered heart
• D. No heart

Answer: (B)

Amphibians have a three-chambered heart, meaning two atria and one ventricle. This arrangement supports double circulation—blood from the body returns to the heart and moves to the lungs (or skin) for oxygen, then back to the heart to be pumped out to the rest of the body. The single ventricle allows some mixing of oxygen-rich and oxygen-poor blood, but a spiral valve in the outflow helps direct blood toward the appropriate arteries, balancing the needs of gas exchange with the body’s circulation. That combination is characteristic of amphibians. Two-chambered hearts are found in fishes, where blood moves in a single loop from atrium to ventricle. Four-chambered hearts provide complete separation of oxygenated and deoxygenated blood and are found in birds and mammals (and some reptiles with special arrangements). No heart is not possible for living vertebrates.

Amphibians have a three-chambered heart, meaning two atria and one ventricle. This arrangement supports double circulation—blood from the body returns to the heart and moves to the lungs (or skin) for oxygen, then back to the heart to be pumped out to the rest of the body. The single ventricle allows some mixing of oxygen-rich and oxygen-poor blood, but a spiral valve in the outflow helps direct blood toward the appropriate arteries, balancing the needs of gas exchange with the body’s circulation. That combination is characteristic of amphibians.

Two-chambered hearts are found in fishes, where blood moves in a single loop from atrium to ventricle. Four-chambered hearts provide complete separation of oxygenated and deoxygenated blood and are found in birds and mammals (and some reptiles with special arrangements). No heart is not possible for living vertebrates.