Which mollusk class is associated with a closed circulatory system?

Which mollusk class is associated with a closed circulatory system?

• A. Cephalopods
• B. Gastropods
• C. Bivalves
• D. Mollusk

Answer: (A)

Cephalopods are the mollusk class with a closed circulatory system. In these animals, blood stays within vessels as it moves through the body, which allows high-pressure, rapid circulation needed for their active, predatory lives. They often have multiple hearts—the branchial hearts pump blood through the gills, and a systemic heart drives it to the rest of the body—creating a more efficient pump than in other mollusks. Their blood uses hemocyanin, a copper-based pigment, which gives blue tinged blood and supports oxygen transport in their active tissues. In contrast, gastropods and bivalves generally rely on an open circulatory system where hemolymph bathes organs in body cavities rather than circulating exclusively within vessels, suited to their slower lifestyles. So the class associated with a closed circulatory system is cephalopods.

Cephalopods are the mollusk class with a closed circulatory system. In these animals, blood stays within vessels as it moves through the body, which allows high-pressure, rapid circulation needed for their active, predatory lives. They often have multiple hearts—the branchial hearts pump blood through the gills, and a systemic heart drives it to the rest of the body—creating a more efficient pump than in other mollusks. Their blood uses hemocyanin, a copper-based pigment, which gives blue tinged blood and supports oxygen transport in their active tissues. In contrast, gastropods and bivalves generally rely on an open circulatory system where hemolymph bathes organs in body cavities rather than circulating exclusively within vessels, suited to their slower lifestyles. So the class associated with a closed circulatory system is cephalopods.