This topic summary covers Knowledge Organiser within The Heart and Circulation for GCSE Biology. Heart structure, cardiac cycle, blood vessels, double circulation, heart rate control, and cardiovascular health It is section 13 of 14 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 13 of 14
Practice
20 questions
Recall
25 flashcards
Knowledge Organiser
Key Terms
- Atria — upper chambers; receive returning blood
- Ventricles — lower chambers; pump blood out
- Valves — prevent backflow; maintain one-way flow
- Coronary arteries — supply heart muscle with blood
- Cardiac output — heart rate x stroke volume
- Double circulation — pulmonary (heart-lungs) + systemic (heart-body)
Must-Know Facts
- Blood flow: Vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta
- Left ventricle wall is thicker than right — pumps blood to entire body at higher pressure
- Pulmonary artery carries deoxygenated blood; pulmonary vein carries oxygenated blood (exception to the general rule)
- Arteries: thick muscular walls, high pressure, carry blood away from heart
- Veins: thin walls, low pressure, valves, carry blood to heart
- Capillaries: one cell thick, allow exchange of oxygen, glucose, and waste
- Cardiac output (ml/min) = heart rate (beats/min) x stroke volume (ml/beat)
- Coronary heart disease: fatty deposits narrow coronary arteries, reducing oxygen supply to heart muscle