Circulatory SystemsCambridge IGCSE Biology: Flashcards
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What is the circulatory system?
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- What is the circulatory system?
- A system of blood vessels with a pump (heart) and valves that ensure one-way flow of blood around the body.
- Define single circulation.
- A circulatory system in which blood passes through the heart once during a complete circuit of the body. Found in fish.
- Define double circulation.
- A circulatory system in which blood passes through the heart twice during a complete circuit of the body. Found in mammals.
- Name the two loops in a double circulation system.
- The pulmonary circulation (heart to lungs and back) and the systemic circulation (heart to body and back).
- What is the role of valves in the circulatory system?
- Valves ensure one-way flow of blood through the heart and blood vessels, preventing backflow.
- Describe the path of blood in single circulation in a fish.
- Blood flows from the heart to the gills for oxygenation, then to the body tissues, and returns to the heart.
- Describe the path of blood in double circulation in a mammal.
- Blood flows from the heart to the lungs for oxygenation, returns to the heart, then flows to the body tissues, and returns to the heart again.
- State one advantage of double circulation over single circulation.
- Blood pressure remains high after passing through the lungs, allowing more efficient delivery of oxygen to body tissues.
- State a second advantage of double circulation.
- Oxygenated and deoxygenated blood are kept separate, ensuring efficient delivery of oxygen to tissues.
- Why is the oxygenated blood kept separate from deoxygenated blood in mammals?
- This allows oxygenated blood to be distributed to body tissues at higher pressure and concentration, improving the efficiency of gas exchange.
- What is the function of the heart in the circulatory system?
- It acts as a muscular pump to maintain the one-way flow of blood through the blood vessels at appropriate pressure.
- Why do mammals require double circulation?
- Mammals are active, warm-blooded organisms with high metabolic demands that require efficient delivery of oxygen to tissues, which double circulation provides.
- Explain why single circulation is sufficient for fish.
- Fish are ectothermic with lower metabolic rates, and the one-way circulation through gills provides adequate oxygenation for their lower oxygen demands.
- Name the type of blood vessel that carries blood away from the heart.
- Arteries carry blood away from the heart.
- Name the type of blood vessel that carries blood towards the heart.
- Veins carry blood towards the heart.