Synonym: Ventriculus sinister, left ventricle
Definition
The left ventricle, as part of the “great” or body’s circulation, is located downstream of the left atrium (atrium sinistrum) and pumps the oxygen-rich blood fresh from the lungs into the aorta and thus into the body’s circulation, where it supplies all the important structures with oxygen.
Anatomy left ventricle
The heart lies rotated around its longitudinal axis in the left chest cavity, so that the right half of the heart lies more against the front chest wall (ventrally), while the left half of the heart points more backwards (dorsally). The left ventricle (left heart chamber) is divided into an inflow and outflow path. It is separated from the atrium by the bicuspid valve or mitral valve.
This is connected to the papillary muscles by tendon threads (chordae tendineae) which originate at the ventricular wall and ensure that the valve does not strike back too violently into the left atrium when it closes before and during the tension phase (systole) of the left ventricle. In the outflow tract, the blood enters the body’s circulation during systole after passing through the aortic valve. The heart chambers (ventricles) differ from each other in their function: the left and right ventricle are separated by the ventricular septum (septum interventriculare), the septum has a thickness of 5-10 mm.
- The wall of the left ventricle is with a thickness of 10-12 mm much thicker than that of the right ventricle. While the left heart has to pump against the much higher pressure of the body’s circulation, which is usually about 120 mmHg, when the blood is ejected into the aorta,
- Must pump the right heart against a much lower pressure, namely the pulmonary pressure prevailing in the lungs, which is below 30 mmHg.
The heart is divided functionally into a left and a right heart. The right heart is part of the “big” circulation (body circulation), via four pulmonary veins (Venae pulmonales) the blood reaches the left atrium and from there via the bicuspid valve (also: mitral valve) into the left ventricle.
After contraction of the left ventricle and opening of the aortic valve, the blood enters the aorta, through which the blood flows through the body via various vessels and supplies it with oxygen (and other nutrients). The action of the heart is roughly divided into two sections, diastole and systole. In the left heart, this cycle proceeds as follows: This cardiac action, consisting of systole and diastole, takes place synchronously and according to the same principle in the right ventricle, from which the blood is first pumped into the pulmonary circulation.
After it has been saturated with oxygen there, it enters the left atrium and the cycle of diastole and systole is repeated again.
- During diastole, the muscles of the ventricle are relaxed. The AV valve (i.e. the valve between the atrium and the ventricle, in the left heart the bicuspid valve) is opened and the ventricle is filled with blood.
- Systole is the phase of tension.
The AV valve is closed so that no blood flows from the ventricle back into the atrium during the subsequent tension (contraction) of the ventricle. During the contraction phase of systole, the aortic valve is also closed, so the blood remains in the ventricle for the time being. As soon as the pressure in the chamber, which is created by the contraction of the muscles, is high enough, the aortic valve opens and the blood flows out of the chamber into the body’s circulation.