The heart and blood vessels — AQA GCSE Biology
Test yourself on The heart and blood vessels with AQA GCSE practice questions.
7 days Premium · Then free forever · No card, no charge
The heart and blood vessels explained
Deoxygenated blood returns from the body through the vena cava into the right atrium.
Read the full explanation
The right atrium contracts, pushing blood through the tricuspid valve into the right ventricle. When the right ventricle contracts, blood leaves through the pulmonary artery to the lungs. In the lungs, oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli to be exhaled. The right ventricle has a thinner muscular wall than the left because the lungs are close and the required pressure is lower. Students should link the ventricle's contraction to blood flow and the lung's structure to efficient gas exchange.
Your focus
- Describe the route of blood from the right atrium to the lungs
- Explain how gas exchange occurs in the alveoli
- Relate the structure of the right ventricle to its function
The heart and blood vessels exam tips
Marking Points
- States that the right ventricle receives deoxygenated blood from the right atrium
- Describes the right ventricle contracting to pump blood through the pulmonary artery to the lungs
- Identifies the lungs as the site of gas exchange where oxygen enters and carbon dioxide leaves the blood
- Links the thinner wall of the right ventricle to the lower pressure needed to reach the lungs
- Explains that oxygen and carbon dioxide diffuse between alveoli and blood down concentration gradients
Examiner Tips
- 💡Use the terms deoxygenated and oxygenated accurately when describing blood flow
- 💡Link the thickness of the ventricle wall to the distance and pressure required
- 💡Practise tracing blood from the vena cava to the lungs and back to the heart
Common Mistakes
- Saying the right ventricle pumps oxygenated blood; correct this by stating it pumps deoxygenated blood to the lungs
- Confusing the pulmonary artery with the aorta; correct this by stating the pulmonary artery carries blood to the lungs
- Stating that gas exchange occurs in the bronchi; correct this by identifying the alveoli as the exchange surface