'Heart block' is a disease which can result in a lower than normal heart rate. A doctor treating a person with heart block found that electrical impulses were initiated as normal but were not correctly conducted to the ventricles, so the rate of ventricular contraction was slowed. Which parts may not be functioning correctly in the person with heart block? 1 atrioventricular node (AVN) 2 Purkyne tissue 3 sinoatrial node (SAN)

1 and 2

1 and 3

2 and 3

3 only

Biology

IGCSE&ALevel

CAIE

Exam No：9700_w24_qp_11 Year：2024 Question No：32

Answer:

Knowledge points:

8.3.1 describe the external and internal structure of the mammalian heart

8.3.2.1 atria and ventricles

8.3.2.2 left ventricle and right ventricle

8.3.3 describe the cardiac cycle, with reference to the relationship between blood pressure changes during systole and diastole and the opening and closing of valves

8.3.4 explain the roles of the sinoatrial node, the atrioventricular node and the Purkyne tissue in the cardiac cycle (knowledge of nervous and hormonal control is not expected)

Answer:

Knowledge points:

Solution:

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