★ Must-know
📌 An open circulatory system requires less energy to operate or maintain than a closed system, but moves less blood to metabolically active organs and tissues with high oxygen requirements.
Further detail
★ Must-know
Further detail
1. Which structures can facilitate gas exchange between an animal’s internal and external environments?
2. A biologist identifies a structure that enables gases to pass between an animal’s body and its surroundings. Which finding is an example of such a gas-exchange surface?
3. What distinguishes an open circulatory system from one in which blood stays enclosed in vessels?
What facilitates gas exchange between an animal’s internal and external environments?
Exchange surfaces such as spiracles, gills, alveoli, and skin.
What circulates through an open circulatory system and bathes its internal tissues?
Haemolymph.
How does an open circulatory system compare with a closed system in operating energy and blood delivery?
It requires less energy but moves less blood to metabolically active, high-oxygen tissues.
What keeps blood separate from body tissues in a closed circulatory system?
Blood remains enclosed within blood vessels.
What pumps blood through a closed circulatory system?
A heart.
What pressure generally characterizes a closed system compared with an open system?
Higher pressure.
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