Why ventricle has a thicker wall

The ventricles of the heart have thicker muscular walls than the atria. This is because blood is pumped out of the heart at greater pressure from these chambers compared to the atria. The left ventricle also has a thicker muscular wall than the right ventricle, as seen in the adjacent image.

This is due to the higher forces needed to pump blood through the systemic circuit around the body compared to the pulmonary circuit. There are four valves within the heart which serve to prevent backflow of blood as it passes through the various chambers of the heart and out through the associated arteries.

The tricuspid valve is positioned between the right atrium and ventricle, and the mitral valve sits between the left atrium and ventricle, as seen in the adjacent image. As blood is pumped out of the ventricles through the aorta and the pulmonary arteries, these valves close to ensure the blood does not get pumped back into the respective atria it came from. The pulmonary valve sits between the right ventricle and the pulmonary artery. Its role is to prevent the backflow of blood into the right ventricle after it contracts.

The aortic valve sits between the left ventricle and the aorta and prevents backflow of blood into the left ventricle after it contracts. These phases can be seen in the following image. The heart beat is controlled by the sympathetic and parasympathetic branches of the autonomic nervous system.

The sympathetic system stimulates the heart to beat faster while the parasympathetic system returns the heart rate to its normal resting level. Electrical impulses action potentials from both systems are sent to the sino-atrial SA node. This is shown on the below image. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.

Skip to navigation Skip to main content Site map Accessibility Contact us. Search this site Search all sites Search. Go to whole of WA Government Search. Open search bar Open navigation Submit search. Facebook Youtube Twitter. Home How your heart works. How your heart works What is your heart? There are 4 chambers: left atrium left ventricle right atrium right ventricle.

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