THORAX ABDOMEN AND PELVIS

MEDICAL

HEART AND PERICARDIUM

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

Which cardiac conducting system structures are responsible for establishing the rate of cardiac contraction?

A	Pacemaker (nodal) cells
B	Plateau cells
C	Conducting cells
D	Action potentiating cells

Explanation:

Detailed explanation-1: -However, the cells of the sinoatrial node (SAN) have the most rapid intrinsic excitation rate, and they establish the rhythmic contractions of the myocardium. The electrical impulses originating at the SAN are due to the presence of a specialized subset of pacemaker cells that differentiate from cardiomyocytes.

Detailed explanation-2: -Your sinoatrial node is sometimes called your heart’s natural pacemaker. It sends the electrical impulses that start the heartbeat. The SA node is in the upper part of your heart’s right atrium.

Detailed explanation-3: -The SA node is the natural pacemaker of the heart. You may have heard of permanent pacemakers (PPMs) and temporary pacing wires (TPWs) which are used when the SA node has ceased to function properly. The SA node releases electrical stimuli at a regular rate, the rate is dictated by the needs of the body.

Detailed explanation-4: -Electrical impulses most quickly arise in the spontaneously firing cells of the sinoatrial (SA) node commonly called the ‘pacemaker. ‘ The SA node is located at the junction of the superior vena cava and the right atrium.

There is 1 question to complete.