Human Heart

The human heart is a vital organ composed of several structures that work together to pump blood throughout the body. Here's an overview of its structure:

1. Chambers:
- Atria: There are two atria (singular: atrium) - the right atrium and the left atrium. They receive blood returning to the heart.
- Ventricles: There are two ventricles - the right ventricle and the left ventricle. Ventricles pump blood out of the heart.

2. Valves:
- Atrioventricular (AV) Valves: These are the tricuspid valve (between the right atrium and right ventricle) and the mitral valve (between the left atrium and left ventricle). They prevent backflow of blood into the atria when the ventricles contract.
- Semilunar Valves: The pulmonary valve (between the right ventricle and pulmonary artery) and the aortic valve (between the left ventricle and aorta). They prevent blood from flowing back into the ventricles after contraction.

3. Blood Vessels:
- Aorta: The largest artery in the body, originating from the left ventricle, carrying oxygen-rich blood to the body.
- Pulmonary Artery: Artery originating from the right ventricle, carrying deoxygenated blood to the lungs for oxygenation.
- Pulmonary Veins: Veins carrying oxygenated blood from the lungs to the left atrium.
- Vena Cava: Two major veins - the superior vena cava and the inferior vena cava - carrying deoxygenated blood from the body back to the right atrium.

4. Muscles and Walls:
- Myocardium: The thick muscular layer of the heart responsible for contraction and pumping of blood.
- Pericardium: A protective sac enclosing the heart, consisting of two layers: the outer fibrous pericardium and the inner serous pericardium.

The heart's function involves receiving deoxygenated blood from the body, pumping it to the lungs for oxygenation, receiving oxygenated blood from the lungs, and pumping it back out to the body. Its rhythmic contractions (heartbeat) maintain circulation, ensuring oxygen and nutrients reach the body's tissues and organs.
By: via Human Heart