Blood flow in the heart is done by the contraction of the heart muscle.

The cardiac cycle is divided into two periods:

1. Diastole - The ventricle muscle is relaxed

2. Systole - The ventricle muscle is contracted

The circulation of blood can be divided into two cycles: the Systemic Cycle and the Pulmonary Cycle.

The heart consists of four chambers:

Right and Left Atrium, and the Right and Left Ventricles.

The Atrium is connected to Ventricles via valves and the right and left sides are separated by a septum.

The heart consists of four key valves:

 - Those between the Atrium and the Ventricles - On the right side the Tricuspid Valve (3 cusps), and on the left side Mitral Valve (2 cusps).

- Those between the Ventricles and out of the heart, commonly known as the Semilunar Valves (3 cusps) - On the right side the Pulmonary Valve and on the left side Aortic Valve.

The heart consists of four chambers:

Right and Left Atrium, and the Right and Left Ventricles.

The Atrium is connected to Ventricles via valves and the right and left sides are separated by a septum.

The heart muscle itself is composed of different layers, which can be divided into three main layers (from outside to inside):

1. Pericardium
2. Myocardium
3. Endocardial Layer (Endocardium)