CAIE IGCSE Biology 9.2.10 How the Heart Pumps
Practise sequencing atrial and ventricular contractions and explaining pressure-driven opening and closing of valves.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Practise sequencing atrial and ventricular contractions and explaining pressure-driven opening and closing of valves.
Heart rate is influenced by electrical impulses from the brain.
The electrical activity of the heart can be recorded on an ECG.
Fig. 3.1 shows an ECG of one heartbeat.

Fig. 3.1
Table 3.1 shows how the electrical activity, during one heartbeat, corresponds to the opening and closing of the valves in the heart.
Complete Table 3.1 using the words 'open' and 'closed'.

Table 3.1
Complete correct answer:
Complete Table 3.1:
- P, atria contract: atrioventricular valves open; semilunar valves closed.
- QRS, ventricles contract: atrioventricular valves closed; semilunar valves open.
- T, atria and ventricles relaxed: atrioventricular valves open; semilunar valves closed.
Marking guidance:
Award one mark per correct row, maximum 3 marks.
State the function of heart valves.
to prevent backflow / AW ; ensures one-way flow of blood (through the heart) ;
I pressure changes