9700 · 8.3
Common exam mistakes on 9700 The heart. Learn what loses marks, then practise the topic with Examiner’s Ink.
When describing the cardiac cycle, always link pressure changes directly to valve actions. For example, instead of just saying 'valves close', explain why they close: 'Ventricular pressure rises above atrial pressure, forcing the AV valves closed.' This shows a deeper understanding and earns marks!
The heart's primary function is to pump blood continuously throughout the circulatory system. This ensures that oxygen and nutrients are delivered to all body cells, while waste products like carbon dioxide are removed. To truly master this, explore our free Cambridge Biology 9700 course and tackle past paper questions to solidify your understanding!
Heart valves act as one-way gates, opening and closing passively in response to pressure changes. They prevent the backflow of blood, ensuring it flows in the correct direction through the heart. The atrioventricular valves (bicuspid and tricuspid) prevent backflow into the atria, while the semi-lunar valves (aortic and pulmonary) prevent backflow into the ventricles after contraction.
The left side of the heart, particularly the left ventricle, is considerably more muscular than the right side because it needs to generate much higher pressure to pump oxygenated blood to the entire body (systemic circulation). The right side, in contrast, only pumps deoxygenated blood a shorter distance to the lungs (pulmonary circulation) at a lower pressure, preventing damage to the delicate lung capillaries.