Question

Explain the Structure and Funtion Of Human Heart?

Answer 1

The human heart has four chambers, the right atrium, the right ventricle, the left atrium and the left ventricle. The right and left sides are completely seperated by the septum, this is so that the oxgenated blood and deoxygenated blood are kept seprate and are not able to mix, allowing for maximum oxygenation. The left side carries oxygenated blood and the right side carries deoxygenated blood. There are four sets of valves, two sets of semi-lunar valves, one set between the right ventricle and the pulmonary artery and the other set between the left ventricle and the aorta. There are also two sets of atrioventricular (AV) valves, one set between the right atrium and the right ventricle, which is called the tricuspid valve, the other set of AV valves are between the left atrium and the left ventricle, which is called the bicuspid valve. The valves in the heart are required to prevent backflow of the blood. The ventricle walls are thicker than those of the atria because the ventricles have to pump blood out of the heart to different parts of the body so require more strength to do this, where as the atria only have to pump blood into the ventricles. The left ventricle wall is thicker than the right ventricle wall because the left ventricle has to pump blood to the whole body, where as the right ventricle only pumps blood to the lungs, which is a shorter distance.
FUNCTION
The function of heart is pretty much like a water pumping motor. Heart receives deoxygenated blood from all over the body, in its right atrium. Then it pumps this deoxygenated blood towards the lungs. Lungs provides oxygen to the blood and then blood is send back to heart in leftatrium.

Hope it help you!!!!

Answer 2

The human heart is an organ that pumps blood throughout the body via the circulatory system, supplying oxygen and nutrients to the tissues and removing carbon dioxide and other wastes.
In humans, the heart is roughly the size of a large fist and weighs between about 10 to 12 ounces (280 to 340 grams) in men and 8 to 10 ounces (230 to 280 grams) in women.

STRUCTURE:The human heart has four chambers: two upper chambers (the atria) and two lower ones (the ventricles). The right atrium and right ventricle together make up the "right heart," and the left atrium and left ventricle make up the "left heart." A wall of muscle called the septum separates the two sides of the heart.

A double-walled sac called the pericardium encases the heart, which serves to protect the heart and anchor it inside the chest. Between the outer layer, the parietal pericardium, and the inner layer, the serous pericardium, runs pericardial fluid, which lubricates the heart during contractions and movements of the lungs and diaphragm.

The heart's outer wall consists of three layers. The outermost wall layer, or epicardium, is the inner wall of the pericardium.  The middle layer, or myocardium, contains the muscle that contracts. The inner layer, or endocardium, is the lining that contacts the blood.

The tricuspid valve and the mitral valve make up the atrioventricular (AV) valves, which connect the atria and the ventricles. The pulmonary semi-lunar valve separates the right ventricle from the pulmonary artery, and the aortic valve separates the left ventricle from the aorta. The heartstrings, or chordae tendinae, anchor the valves to heart muscles. The sinoatrial node produces the electrical pulses that drive heart contractions.

FUNCTION:
The heart circulates blood through two pathways: the pulmonary circuit and the systemic circuit.

In the pulmonary circuit, deoxygenated blood leaves the right ventricle of the heart via the pulmonary artery and travels to the lungs, then returns as oxygenated blood to the left atrium of the heart via the pulmonary vein.

In the systemic circuit, oxygenated blood leaves the body via the left ventricle to the aorta, and from there enters the arteries and capillaries where it supplies the body's tissues with oxygen. Deoxygenated blood returns via veins to the venae cavae, re-entering the heart's right atrium.
After the blood leaves the heart through the aortic valve, two sets of arteries bring oxygenated blood to feed the heart muscle," he said. The left main coronary artery, on one side of the aorta, branches into the left anterior descending artery and the left circumflex artery. The right coronary artery branches out on the right side of the aorta. Blockage of any of these arteries can cause a heart attack, or damage to the muscle of the heart.
A heart attack is distinct from cardiac arrest, which is a sudden loss of heart function that usually occurs as a result of electrical disturbances of the heart rhythm. A heart attack can lead to cardiac arrest, but the latter can also be caused by other problems.

The heart contains electrical "pacemaker" cells, which cause it to contract — producing a heartbeat.

"Each cell has the ability to be the 'band leader' and [to] have everyone follow," Phillips said. In people with an irregular heartbeat, or atrial fibrillation, every cell tries to be the band leader, which causes them to beat out of sync with one another.

A healthy heart contraction happens in five stages. In the first stage (early diastole), the heart is relaxed. Then the atrium contracts (atrial systole) to push blood into the ventricle. Next, the ventricles start contracting without changing volume. Then the ventricles continue contracting while empty. Finally, the ventricles stop contracting and relax. Then the cycle repeats. 

Valves prevent backflow, keeping the blood flowing in one direction through the heart.