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The human heart has four chambers. The right and left ventricles are the lower two chambers, and the right and left atria are the top two chambers. These four chambers are all connected by valves that control the flow of blood between them. The chambers and valves of the heart and all of the human body’s arteries and veins make up the human cardiovascular system.
The right ventricle functions to perform two jobs. It receives from the right atrium blood that has had its oxygen removed by the body. The ventricle then pumps that blood into the pulmonary artery so it can be moved to the lungs.
The pumping that occurs in the ventricles requires more force than the pumping of the atria. This is because the blood travels outside the heart when leaving the ventricles. The aorta, on the other hand, pumps blood to a neighboring chamber. The ventricle’s need to pump the blood farther requires that the walls of the ventricles be thicker than the aorta walls.
The heart is made of chambers that both hold and move blood, so there is a system of valves that prevents blood from moving in the wrong direction. Between the right atrium and the right ventricle is the tricuspid valve. The pulmonary valve is between the right ventricle and the pulmonary artery. These two valves keep the flow of blood going in one direction.
The system moves blood in two parts. Contraction of the right atrium moves blood into the right ventricle via the tricuspid valve. The pulmonary valve is then closed and the right ventricle fills with blood.
After the blood from the right atrium has moved into the right ventricle, the tricuspid valve closes so the blood does not flow backward. The right ventricle contracts and causes the pulmonary valve to open. The blood then moves freely to the lungs without possible backflow because the pulmonary valve closes after the ventricle has contracted completely.
In some people, the ventricles can become enlarged, or dilated. Right ventricle dilation is rarer than left ventricle dilation. In either case, the size increase is generally a response by the heart to heal damage by thinning and stretching the muscle. If the heart has been damaged by previous heart attacks, alcohol abuse, exposure to heavy metals, or other harm, then there is a risk of ventricular dilation.