a. Ventricles contract simultaneously, but the myocardial layer of the left vent

Question

a. Ventricles contract simultaneously, but the myocardial layer of the left ventricle is significantly thicker than that of the right ventricle. Compare the volume of blood and the pressure with which blood is ejected from the two ventricles during ventricular systole?

2. During a heart transplant, the vagus nerve is severed, so no parasympathetic impulses reach the transplanted heart. In the absence of therapeutic intervention, how would the heart rate of recently transplanted heart compare with the normal heart rate (unless or until nerve regrowth occurs)

3.Explain what makes the accumulation of fluid in the pericardial space a life-threatening situation

4. Explain the importance of Purkinje fibers

Explanation / Answer

1) The myocardial layer of the left ventricle has thicker wall than that of right ventricle because left ventricle has to pump the blood into the whole body which goes through the aorta but the right ventricle only pumps the blood to the lungs through the pulmonary artery. The pulmonary artery has high pressure so the deoxygenated blood flows from the right ventricle to the capillaries of the lungs and due to low pressure in the pulmonary vein, the oxygenated blood flows from the capillaries of the lungs to the left ventricle of the heart. Thus the oxygenated blood flows from the left ventricle to the whole body which needs high pressure in the ventricle and the thicker wall of the ventricle favors to tolerate the pressure which is given by the blood.

The volume and the pressure of blood flow from the left ventricle is more than that of right ventricle during ventricular systole because left ventricle distributes the oxygenated blood to the whole parts of the body which needs high pressure to execute the blood flow through the aorta which is bigger in size. Thus the high volume of blood needs high pressure in left ventricle to flow the blood to the whole body.

The right ventricle only flow the blood to the lungs which is in less volume so the pressure in right ventricle is low than that of left ventricle.

2) Due to denervation of vagus nerve the heart rate increases to 90 to 100 beats per minute than that of normal heart rate.

3) Due to the increase in fluid in the pericardial cavity it may causes inflammation of pericardium which leads to intrapericardial pressure. This occurs due to the limited space between two pericardium. This is known as pericardium effusion. A pericardium effusion affects the normal function of heart due to the adverse pressure on the heart which is exerted by the excess fluid accumulated in the pericardium space and causes cardiogenic shock and is known as cardiac temponade.

4) Purkinje fibers is a conducting fiber present in the ventricular walls which is composed of excitable cells that helps to conduct the cardiac action potential impulse rapidly from both the right and left bundle to the myocardium of the ventricle. This helps the synchronized contraction of the ventricle in maintaining a consistent heart rhythm.

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