Which term describes openings that allow hemolymph into the heart in insects?

Which term describes openings that allow hemolymph into the heart in insects?

• A. Ostia
• B. Atria
• C. Peritoneum
• D. Systole

Answer: (A)

Insects use an open circulatory system where the dorsal vessel acts as the heart. Along this vessel are small slit-like openings called ostia, which admit hemolymph from the body cavity back into the heart. These ostial openings often have one-way valves that close when the heart contracts, preventing backflow and pushing the hemolymph forward into the aorta. This is different from terms like atria, which are true heart chambers in many animals; peritoneum is simply the lining of the body cavity; and systole refers to the contraction phase. So the openings that allow hemolymph into the heart are ostia.

Insects use an open circulatory system where the dorsal vessel acts as the heart. Along this vessel are small slit-like openings called ostia, which admit hemolymph from the body cavity back into the heart. These ostial openings often have one-way valves that close when the heart contracts, preventing backflow and pushing the hemolymph forward into the aorta. This is different from terms like atria, which are true heart chambers in many animals; peritoneum is simply the lining of the body cavity; and systole refers to the contraction phase. So the openings that allow hemolymph into the heart are ostia.