OCR Biology - Heart graph questions

Phaeochromocytoma is a rare tumour of adrenal gland tissue. It causes increased hormone release from the adrenal glands.
Fig 21.2 shows three ECG traces showing the heart rhythms of three different patients. Match the trace to the description.

• Patient Y has phaeochromocytoma.

• Middle trace

• Patient Z has bradycardia.

• Bottom trace

• Patient X has a normal heart rhythm.

• Top trace

The ECG traces below show four abnormal heartbeats recorded for six seconds.
Which of the traces, A to D, shows atrial fibrillation?

• A

• B

• C

• D

The ECG traces below show four abnormal heartbeats recorded for six seconds.
Which of the traces, A to D, shows an ectopic heartbeat?

• A

• B

• C

• D

The ECG traces below show four abnormal heartbeats recorded for six seconds.
Which of the traces, A to D, shows bradycardia?

• A

• B

• C

• D

During exercise the cardiac output of an athlete is 28 dm³ min^–1 and their stroke volume is 160 cm³.
How many heart beats occur when the athlete exercises for five minutes? Assume the cardiac output and stroke volume stay constant during the exercise time.

• 22

• 175

• 875

• 4480

Which of the options, A to D, on the diagram below shows the time at which the SAN sends out a wave of excitation to initiate a heartbeat?

• A

• B

• C

• D

The sounds of the heartbeat due to heart valves closing can be described as ‘lub-dub’. The ‘lub’ sound occurs at the beginning of ventricular systole.

Which of the options, A to D, describes what is happening when the ‘lub’ sound is heard?

• semilunar valves opening and blood entering the ventricles

• semilunar valves closing and blood entering the ventricles

• atrio-ventricular valves opening and blood leaving the ventricles

• atrio-ventricular valves closing and blood leaving the ventricles

The diagram shows the changes in pressure in the left atrium, left ventricle and aorta in a single cardiac cycle.
Which letter shows the point at which the semilunar valve opens?

• A

• B

• C

• D

Which of the statements about the heart is correct?

• Contraction of the ventricles is known as ventricular systole.

• Deoxygenated blood enters the heart by the pulmonary vein.

• The pressure in the ventricles is always greater than in the atria because of the thicker ventricle wall.

• The wall of the left ventricle is less thick because it only has to pump blood to the lungs