How Heart works?
The heart has two sides, separated by an inner wall called the septum. The right side of the heart pumps blood to the lungs to pick up oxygen. The left side of the heart receives the oxygen-rich blood from the lungs and pumps it to the body.
The heart has four chambers and four valves and is connected to various blood vessels. Veins are blood vessels that carry blood from the body to the heart. Arteries are blood vessels that carry blood away from the heart to the body.
Heart Chambers
The heart has four chambers or "rooms."
- The atria (AY-tree-uh) are the two upper chambers that collect blood as it flows into the heart.
- The ventricles (VEN-trih-kuhls) are the two lower chambers that pump blood out of the heart to the lungs or other parts of the body.
Heart Valves
Four valves control the flow of blood from the atria to the ventricles and from the ventricles into the two large arteries connected to the heart.
- The tricuspid (tri-CUSS-pid) valve is in the right side of the heart, between the right atrium and the right ventricle.
- The pulmonary (PULL-mun-ary) valve is in the right side of the heart, between the right ventricle and the entrance to the pulmonary artery. This artery carries blood from the heart to the lungs.
- The mitral (MI-trul) valve is in the left side of the heart, between the left atrium and the left ventricle.
- The aortic (ay-OR-tik) valve is in the left side of the heart, between the left ventricle and the entrance to the aorta. This artery carries blood from the heart to the body.
Valves are like doors that open and close. They open to allow blood to flow through to the next chamber or to one of the arteries. Then they shut to keep blood from flowing backward.
When the heart's valves open and close, they make a "lub-DUB" sound that a doctor can hear using a stethoscope.
- The first sound—the "lub"—is made by the mitral and tricuspid valves closing at the beginning of systole (SIS-toe-lee). Systole is when the ventricles contract, or squeeze, and pump blood out of the heart.
- The second sound—the "DUB"—is made by the aortic and pulmonary valves closing at the beginning of diastole (di-AS-toe-lee). Diastole is when the ventricles relax and fill with blood pumped into them by the atria.
What are heart valves?
The heart consists of four chambers, two atria (upper chambers) and two ventricles (lower chambers). There is a valve through which blood passes before leaving each chamber of the heart. The valves prevent the backward flow of blood. These valves are actual flaps that are located on each end of the two ventricles (lower chambers of the heart). They act as one-way inlets of blood on one side of a ventricle and one-way outlets of blood on the other side of a ventricle. Each valve actually has three flaps, except the mitral valve, which has two flaps. The four heart valves include the following:
- tricuspid valve: located between the right atrium and the right ventricle
- pulmonary valve: located between the right ventricle and the pulmonary artery
- mitral valve: located between the left atrium and the left ventricle
- aortic valve: located between the left ventricle and the aorta
How do the heart valves function?
As the heart muscle contracts and relaxes, the valves open and shut, letting blood flow into the ventricles and atria at alternate times. The following is a step-by-step illustration of how the valves function normally in the left ventricle:
- After the left ventricle contracts, the aortic valve closes and the mitral valve opens, to allow blood to flow from the left atrium into the left ventricle.
- As the left atrium contracts, more blood flows into the left ventricle.
- When the left ventricle contracts again, the mitral valve closes and the aortic valve opens, so blood flows into the aorta.
What is heart valve disease?
Heart valves can have one of two malfunctions:
- regurgitation
The valve(s) does not close completely, causing the blood to flow backward instead of forward through the valve. - stenosis
The valve(s) opening becomes narrowed or does not form properly, inhibiting the flow of blood out of the ventricle or atria. The heart is forced to pump blood with increased force in order to move blood through the stiff (stenotic) valve(s).
Heart valves can have both malfunctions at the same time (regurgitation and stenosis). When heart valves fail to open and close properly, the implications for the heart can be serious, possibly hampering the heart’s ability to pump blood adequately through the body. Heart valve problems are one cause of heart failure.
Arteries
The arteries are major blood vessels connected to your heart.
- The pulmonary artery carries blood from the right side of the heart to the lungs to pick up a fresh supply of oxygen. (Right side of heart ---> Lung ---> Pick up oxygen)
- The aorta is the main artery that carries oxygen-rich blood from the left side of the heart to the body. (left side of heart ---> body, for providing oxygen)
- The coronary arteries are the other important arteries attached to the heart. They carry oxygen-rich blood from the aorta to the heart muscle, which must have its own blood supply to function. (left side of heart ---> heart muscle)
pericardium - the membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane. It is a double-walled sac containing the heart and the roots of the great vessels. The pericardial sac has two layers, a serous layer and a fibrous layer. It encloses the pericardial cavity which contains pericardial fluid.
myocardium - is the muscle tissue of the heart
endocardium - is the innermost layer of tissue that lines the chambers of the heart.
Systemic circulation is the part of the cardiovascular system which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart.
Pulmonary circulation is the portion of the cardiovascular system which carries deoxygenated blood away from the heart, to the lungs, and returns oxygenated (oxygen-rich) blood back to the heart. The term pulmonary circulation is readily paired and contrasted with the systemic circulation.
Systemic circulation is the part of the cardiovascular system which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart.
Pulmonary circulation is the portion of the cardiovascular system which carries deoxygenated blood away from the heart, to the lungs, and returns oxygenated (oxygen-rich) blood back to the heart. The term pulmonary circulation is readily paired and contrasted with the systemic circulation.
Pulmonary circulation process
Pulmonary circulation is the movement of blood from the heart, to the lungs, and back to the heart again. Deoxygenated blood leaves the heart, goes to the lungs, and then re-enters the heart; Deoxygenated blood leaves through the right ventricle through the pulmonary artery. From the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle. Blood is then pumped from the right ventricle through the pulmonary valve and into the pulmonary trunk of the pulmonary artery.
From the right ventricle, blood is pumped through the pulmonary semi-lunar valve into the left and right pulmonary arteries (one for each lung) and travels through the lungs.
The pulmonary arteries carry deoxygenated blood to the lungs, where carbon dioxide is released and oxygen is picked up during respiration. Arteries are further divided into very fine capillaries which are extremely thin-walled. Their function is to assist in the carrying of blood to all cells of the body. The pulmonary vein returns oxygenated blood to the left atrium of the heart.
The oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. This blood then enters the left atrium, which pumps it through the bicuspid valve, also called the mitral or left atrioventricular valve, into the left ventricle. From the left ventricle the blood passes through the aortic valve to the aorta. The blood is then distributed to the body through the systemic circulation before returning again to the pulmonary circulation.
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