A Level Biology Practice Exam

What is the function of Purkyne fibres in the heart?

1. Conducting oxygen-rich blood

2. Conducting waves of excitation

3. Suppressing heart rate

4. Regulating blood pressure

The correct answer is: Conducting waves of excitation

Purkyne fibres are specialized muscle fibres located within the heart's conduction system. Their primary function is to conduct waves of excitation, which play a critical role in the coordination of heartbeat. These fibres transmit the electrical impulses generated by the sinoatrial (SA) node, allowing for synchronized contraction of the ventricles. This ensures that the heart effectively pumps blood throughout the body. The conduction system also helps maintain a rhythmical heartbeat, enabling the atria to contract and fill the ventricles with blood before the ventricles themselves contract. This mechanism is essential for maintaining efficient blood flow and overall cardiovascular health. Through this role, Purkyne fibres contribute significantly to the heart's ability to function as a pump, highlighting their importance in the circulatory system.