21 October 2016

Heart's Main Components or Structural Components of the Human Heart

The four parts, or chambers, of the heart include the right and left atria and the right and left ventricles. Each chamber has its own valve that allows blood to flow into and out of the chamber. The heart valves keep blood flowing in one direction through the heart.

The four valves of the heart include the tricuspid valve, the mitral vale, the pulmonary valve and the aortic valve. The tricuspid valve lies between the right atrium and the right ventricle and opens to allow blood to flow into the right ventricle from the right atrium. The mitral valve lies between the left atrium and the left ventricle. This valve allows blood to flow into the left ventricle from the left atrium. The pulmonary valve connects the heart to the lungs and allows blood to flow out of the right ventricle into the lungs.

The aortic valve connects the heart to the systemic circulation and allows blood to flow from the left ventricle to the rest of the body. The four chambers of the heart do not contract at the same time. They contract separately to push blood through the heart, lungs and throughout the entire body. As the heart chambers relax, they are in diastole. As they contract, they are in systole.
Heart's Main Components or Structural Components of the Human Heart

The human heart is arguably the most important organ in the body, because it serves as the primary pump for the circulatory system. To analyze the individual functions of the heart, scientists typically divide the organ into four main regions: the left and right ventricle, and the left and right atrium. Within these four zones are numerous important structures that together allow the human heart to function.

Right Atrium
The right atrium is where the flow of blood through the heart begins. Blood circulating through the body enters the right atrium, which is on the lower right side of the heart. Blood enters the right atrium through structures including the superior and inferior vena cavas. After entering through the vena cavas, the blood exits the right atrium to the right ventricle, which it does through the tricuspid valve. On both sides of the heart, atria are separated from ventricles by these cuspid valves, also called atrioventricular valves.

Right Ventricle
From the right atrium, blood travels next through the tricuspid valve into the heart's right ventricle. The two ventricles of the heart are thick-walled veins that rapidly and efficiently move heart between the atria and back into the body. After moving through the right ventricle, blood moves on to the pulmonary valve, which pushed deoxygenated blood into the lungs, where it receives oxygen. This is a major function of the human heart, which maintains a certain level of oxygenation in the circulatory system's blood.

Left Atrium
After receiving oxygen in the lungs, blood moves from the lungs back to the heart via the left atrium. The blood re-enters the heart here through a different set of pulmonary valves. In this case, unlike when blood exits the heart for the lungs, the blood now uses the left set of pulmonary veins to return to the left atrium. To move onto the left ventricle, blood exits via the mitral, also known as the bicuspid valve. The oxygenated blood is now prepared to enter the body.

Left Ventricle
To enter the body and circulate, blood must travel from the left atrium via the left ventricle. Importantly, the left ventricle is separated from the aorta via the aortic valve. Using the ascending aorta, the blood is now ready to exit the heart and circulate through the body. It does this through a large series of veins and arteries. Some of the most important and primary pathways from the heart include the brachiocephalic artery, the left common carotid artery and the left subclavian artery. These are just some of the largest and most important arteries, but many others exist.

Heart Chambers, Valves, Vessels, Wall and Conduction System
The heart is made up of four chambers. The upper two chambers are called atria (singular: atrium) and the lower two are known as ventricles.
Muscular walls, called septa or septum, divide the heart into two sides.
On the right side of the heart, the right atrium and ventricle work to pump oxygen-poor blood to the lungs.
On the left side, the left atrium and ventricle combine to pump oxygenated blood to the body.

There are four valves within the heart:
The tricuspid valve is between the right atrium and the right ventricle.
The pulmonary valve is between the right ventricle and the pulmonary artery.
The mitral valve is between the left atrium and the left ventricle.
The aortic valve is located between the left ventricle and the aorta.
These valves open when blood passes through them and then close to keep the blood from flowing in the wrong direction.

The four chambers of the heart are attached to major veins or arteries that either bring blood into or carry blood away from the heart.
The atria are the receiving stations of the heart. The right atrium receives its supply of oxygen-poor blood from the two largest veins in the body, the superior and inferior vena cava.
The left atrium receives blood that has been oxygenated in the lungs from the pulmonary veins. Both atria then pump their supply of blood into the ventricles.
The ventricles are the shipping stations of the heart. The right ventricle pumps oxygen-poor blood into the lungs through the pulmonary artery while the left ventricle pumps oxygenated blood to the body through the aorta, the largest artery in the body.

The heart wall consists of three layers: the endocardium, myocardium and epicardium.
The endocardium is the thin membrane that lines the interior of the heart.
The myocardium is the middle layer of the heart. It is the heart muscle and is the thickest layer of the heart.
The epicardium is a thin layer on the surface of the heart in which the coronary arteries lie.
The pericardium is a thin sac the heart sits in, often filled with a small amount of fluid, which separates the heart from the other structures in the chest such as the lungs.

The conduction system is the heart's own built-in pacemaker. This special tissue sets the heart rate and allows the upper and lower chambers to communicate with each other so they can function in a coordinated fashion.

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