What type of circulatory system do echinoderms have?

What type of circulatory system do echinoderms have?

• A. Closed circulatory system with a heart
• B. Open circulatory system with a heart
• C. Open circulatory system with no heart
• D. No circulatory system

Answer: (C)

Echinoderms don’t have a heart or a traditional circulatory system. They rely on a water vascular system, plus circulating coelomic fluid, to assist movement, feeding, and basic transport of substances, but this isn’t a closed network of vessels carrying blood like in hearts or arteries. The water vascular system uses seawater to power tube feet, while gas exchange and nutrient distribution occur mainly by diffusion through tissues. In short, they lack a true circulatory system in the conventional sense; their hydraulic water-based system handles functions that a circulatory system would normally manage.

Echinoderms don’t have a heart or a traditional circulatory system. They rely on a water vascular system, plus circulating coelomic fluid, to assist movement, feeding, and basic transport of substances, but this isn’t a closed network of vessels carrying blood like in hearts or arteries. The water vascular system uses seawater to power tube feet, while gas exchange and nutrient distribution occur mainly by diffusion through tissues. In short, they lack a true circulatory system in the conventional sense; their hydraulic water-based system handles functions that a circulatory system would normally manage.