Biology 9700 · AS & A Level · The heart

The heart — practice question

Aortic stenosis is a disorder of a heart valve where the opening of the aortic semi-lunar valve is reduced in size. What effect could aortic stenosis have on the heart’s structure and function?

  • AThe tendons of the heart valves are weakened by blood being forced back through the bicuspid/left atrio-ventricular valve into the left atrium.
  • BThe cardiac muscle of the left ventricle wall is thinned by blood leaking out of the left ventricle during ventricular diastole.
  • CThere is less cardiac muscle in the left ventricle and reduced diastolic blood pressure, caused by the smaller blood volume entering the left atrium.
  • DThe wall of the left ventricle thickens, leading to an enlarged heart and inability to relax and fill completely during diastole.

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