Which of the following statement best describes the function of sinoatrial node?
Correct answer: D. It sends out electrical impulses to atrial muscles causing both atria to contract.
- A. It sends out electrical impulses to ventrictes to contract.
- B. It is present at upper end of the left atrium
- C. It consists of small number of diffusely oriented cardiac fibers
- D. It sends out electrical impulses to atrial muscles causing both atria to contract.
Explanation
Explanation:SA node or the pacemaker is located in the right atrium and it sends out impulses causing both Atria to contract. This option is incorrect because the SA node is responsible for initiating and coordinating the contraction of the Atria, not the ventricles. This option is incorrect because the SA node is located in the right atrium, near the entrance of the superior vena cava. This option is also incorrect because the SA node consists of a group of specialized cardiac muscle cells, not fibers.
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About Cardiac Cycle and Heartbeat
The cardiac cycle describes atrial systole, ventricular systole and diastole, including pressure changes, blood movement and the opening or closing of heart valves. It also covers the conduction pathway from the sinoatrial node through the atrioventricular node, bundle of His and Purkinje fibres, and relates these events to heartbeat sounds.
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