Ventricles of the Heart

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Ventricles of the Heart

Human Heart Cross Section
Human heart cross section showing blood circulation through the heart. jack0m/DigitalVision Vectors/Getty Images

Ventricles of the Heart

The heart is a component of the cardiovascular system that helps circulate blood to the organs, tissues, and cells of the body. Blood travels through blood vessels and is circulated along pulmonary and systemic circuits. The heart is divided into four chambers that are connected by heart valves. These valves prevent the backward flow of blood and keep it moving in the right direction.

The lower two chambers of the heart are called heart ventricles. A ventricle is a cavity or chamber that can be filled with fluid, such as the cerebral ventricles. The heart ventricles are separated by a septum into the left ventricle and the right ventricle. The upper two heart chambers are called atria. Atria receive blood returning to the heart from the body and ventricles pump blood from the heart to the body.

The heart has a three-layered heart wall composed of connective tissue, endothelium, and cardiac muscle. It is the muscular middle layer known as myocardium that enables the heart to contract. Due to the force needed to pump blood to the body, ventricles have thicker walls than do atria. The left ventricle wall is the thickest of the heart walls.

Function of the Ventricles

The ventricles of the heart function to pump blood to the entire body. During the diastole phase of the cardiac cycle, the atria and ventricles are relaxed and the heart fills with blood. During the systole phase, the ventricles contract pumping blood to the major arteries (pulmonary and aorta). The heart valves open and close to direct the flow of blood between the heart chambers and between the ventricles and major arteries. Papillary muscles in the ventricle walls control the opening and closing of the tricuspid valve and mitral valve.

  • Right ventricle: Receives blood from the right atrium and pumps it to the main pulmonary artery. Blood passes from the right atrium through the tricuspid valve into the right ventricle. Blood is then forced into the main pulmonary artery as the ventricles contract and pulmonary valve opens. The¬†pulmonary artery extends from the right ventricle and branches into left and right pulmonary arteries. These arteries extend to the lungs. Here, oxygen-poor blood picks up oxygen and is returned to the heart via the pulmonary veins.
  • Left ventricle: Receives blood from the left atrium and pumps it to the aorta. Blood returning to the heart from the lungs enters the left atrium and passes through the mitral valve to the left ventricle. Blood in the left ventricle is then pumped to the aorta as the ventricles contract and the aortic valve opens. The aorta carries and distributes oxygen-rich blood to the rest of the body.

Cardiac Conduction

Cardiac conduction is the rate at which the heart conducts the electrical impulses that drive the cardiac cycle. Heart nodes located in the right atrium contract sending nerve impulses down the septum and through out the heart wall. Branches of fibers known as Purkinje fibers relay these nerve signals to the ventricles causing them to contract. Blood is moved along through the cardiac cycle by the constant cycle of heart muscle contraction followed by relaxation.