Which of the following cause the ventricles to contract? A
AV node
B.
AV bundle
O C.
Purkinje fibers
OD
All of the above

D. All of the above

Explanation:

In Human anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.

Generally, the cardiac cycle occurs in two (2) stages;

1. Diastole : in this stage, the ventricles is relaxed and would be filled with blood.

2. Systole: at this stage, the muscles contracts and thus, allow blood to be pushed through the atria.

Cardiac output can be defined as the volume of blood that is being pumped by the mammalian heart through the left and right ventricle per unit time (minute).

The following conducting systems of the heart cause the ventricles to contract;

I. Atrioventricular (AV) node: it's a component of the electrical conduction system of the mammalian heart located in the Koch triangle which connect the ventricles and atria electrically.

II. Atrioventricular (AV) bundle: it's a specialized tissue that transmits electrical impulse from the atrioventricular (AV) node to the Purkinje fibres of the ventricles.

III. Purkinje fibers: it's a network of specialized cells that comprises of glycogen and they transmit cardiac action potentials in a rapid manner from the atrioventricular (AV) bundle to the myocardium of the ventricles.

Furthermore, the right atrioventricular valve (AV) also referred to as the tricuspid valve is located on the right dorsal side of the human heart. The right atrioventricular valve (AV) comprises of three (3) leaflets (flaps) which opens and closes in order to allow for the flow of blood from the right atrium of the human heart to the right ventricle. Also, the right atrioventricular valve is saddled with the responsibility of preventing blood from flowing backward in the mammalian heart.

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