Matters Of the Heart-Anatomy (Part 1)

The heart is comprised of four compartments, all of them recieve and pump blood to and from different areas.

The two upper compartments (or chambers) are called the atria. They are comparitively small and are in charge of recieving blood and pumping it to the lower chambers of the heart.

The Heart Chambers:

The Right Atria
Recieves blood from most of the body. (The head, arms legs, stomach, liver, kidneys etc.)

The Left Atria
Recieves blood from the lungs.

Both are very importiant for the ciruculation of oxygenated blood.

The two lower chambers of the heart are called the Ventricles. They are in charge of pumping blood to locations outside of the heart.

The Right Ventricle

Recieves blood from the Right Atria and pumps it to the lungs so it can become oxygenated.

The Left Ventricle

Recieves blood from the Left Atria so it can be pumped (and supply oxygen to) the body's organs.

These compartments are separated from each other by specialized structures: the muscular septum and the valves.

The Septum

The right and left heart are separated by a substance called septum, which is primarily made out of muscle and bundles of nerve tissue. This structure functions as a barrier (so blood going to different locations doesn't mix). It's myocytes also to physically pump blood, and the nerve bundles help in the conduction of electrical impulse from the top of the heart to the bottom.

The Valves

The upper and lower heart is separated by a series of 4 (four) valves. They have two primary functions:

1) Preventing the backflow of blood

2) Insulate the upper heart from the lower heart electronically (this is importiant, we will see why in Physiology Part 2)

The Four Valves:

The Atrio-Ventricular Valves

These two valves are relatively large and are located in between the atria and ventricles of the heart. They are:

The Tricuspid Valve-

This valve is on the right side of the heart, in between the right atria and the right ventricle. It has three little cusps (that kind of look like parachutes) that close when the right ventricle is full to prevent it from spilling blood back into the right atria.

Bicuspid Valve (sometimes called the Mitral valve just to make things confusing)-

This valve is on the left side of the heart; between the left atria and the left ventricle. It is made out of two little parachute-like cusps that prevent blood from flowing backward into the left atria and the lungs/pulmonary system.

The Semilunar Valves

There are two more valves in the heart. They act as doorways in-between the ventricles and the arteries that the ventricles empty into. They are called the Semilunar valves because they are shaped like a half-moon.

The Pulmonary Valve-

This valve is located in-between the right ventricle and the artery that carrys blood to the lungs so it can become oxygenated blood (this artery is called the 'Pulmonary Artery'). This valve is importiant because it prevents blood from flowing backward into the heart.

The Aortic Valve-

This valve is located in-between the Left Ventricle and the artery that carries blood to the bodies to supply oxygen to them (this artery is called the 'aorta') This valve is importiant because it prevents blood from flowing backward into the left ventricle of the heart.