The heart plays a central role in the human cardiovascular system because it is the motor of the circulatory system. The blood from the body’s circulatory system first reaches the right half of the heart. From there the blood is pumped into the lungs, where it is supplied with oxygen. From the pulmonary circulation the blood flows to the left half of the heart, from where it is transported through the aorta into the entire body circulation. In its pumping function, the heart adapts to the respective situation of the body, because different demands are placed on the cardiovascular system depending on whether a person is lying down, standing or exerting himself physically.
Tasks of the left ventricle
The left ventricle, also called the left ventricle, is responsible for pumping blood into the body’s circulation. In the relaxation phase, the so-called diastole, the left ventricle is filled with oxygen-rich blood from the pulmonary circulation. This blood first reaches the left atrium from the lungs.
From there it is transported through the mitral valve into the left ventricle. During the contraction phase, known in medical terminology as systole, the left ventricle pumps the blood through the aortic valve into the aorta, from where it enters the body’s circulation. The left ventricle must apply enough pressure to exceed the blood pressure in the body’s circulation.
Normally, this is about 120 mmHg. Compared to the right ventricle, the left ventricle must therefore apply a significantly higher pressure. Therefore, the layer of heart muscle on the left side is much thicker.
The left ventricle must be able to adapt its pumping activity to the physical activity. During physical activity, the heart therefore beats significantly faster. At the same time, the left ventricle is filled with a larger amount of blood before each beat. By increasing the volume and the beat rate, the cardiac output per minute, i.e. the amount of blood that the heart pumps into the circulation per minute, increases significantly. Only in this way is the heart able to meet the increased demands during a stress phase.
Tasks of the right ventricle
The right ventricle receives the oxygen-poor blood from the body’s circulatory system. This blood is first collected in the right atrium before it is transported through the tricuspid valve into the right ventricle. The right ventricle pumps the blood through the so-called pulmonary valve into the pulmonary vessels so that it is supplied with oxygen in the lungs.
There are two different phases in the pumping function of the right ventricle. The tension phase and the relaxation phase. During the relaxation phase, the right ventricle fills with blood and the heart muscles are relaxed.
When the signal for tension arrives in the right ventricle via the excitation conduction system of the heart, the heart muscle tenses up. As soon as a pressure of about 25 mmHg is reached, which is the maximum pressure that prevails in the pulmonary circulation, the tricuspid valve opens. This allows the blood from the right ventricle to enter the pulmonary circulation. In contrast to the left ventricle, the right ventricle must apply a comparatively low pressure during the contraction phase. Therefore, the muscle layer of the right ventricle is significantly thinner.