The Human Heart
The human heart is known to have 4 chambers, namely: the atria or the 2 upper chambers and the ventricles or otherwise known as the lower 2 chambers. There are 2 sides of the heart; the left which is comprised of the left atrium and left ventricle; and the right side which is the right atrium and right ventricle combined. The two sides of the heart is separated by the septum which is a wall of muscle.
The outer part of the heart is encased in pericardium which is a double walled sac that also helps protect it and makes sure the heart stays in place in the chest. The pericardium has 2 layers which are the parietal pericardium (outer) and the pericardial pericardium (inner). Whenever the diaphragm and lungs move and contract, the pericardial fluid is released and lubricates these layers.
The weight of an average human heart is between 250 to 350 grams or 9 to 12 ounces respectively and may be the size of a large human fist.
The heart’s outer wall is comprised of 3 layers:
- Epicardium (outer layer)
- Pericardium (inner layer)
- Myocardium (middle layer)
The inner layer of the heart or otherwise known as the endocardium is a lining where there is contact with the blood
Valves of the heart:
- Tricuspid valve
- Mitral valve
- Semi-lunar valve
- Aortic valve
These valves are connected to the heart via the heartstrings or chordae tendinae