Biology 9700 · AS & A Level · The heart

The heart — practice question

Fig. 2.1 presents a diagram of a cross-section through a human heart.
(a)[3]

State what the circled structure labelled X is called and what it does.

(b)[3]

Explain why region Y has a thicker wall than region Z.

(c)[5]

Cardiac muscle is called myogenic because it contracts and relaxes on its own. With reference to the structures and tissues in the heart, describe how the cardiac cycle is started and coordinated.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Semilunar (pulmonary) valve correctly identified

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