The heart of a vertebrate is composed of cardiac muscle which is an involuntary striated muscle tissue which is found only within this organ. The cardiac is a special type of muscle which is found in the heart alone and is nearly dark red in color. The heart pumps the blood through the blood vessels. There a re three main types of blood vessels namely the arteries, capillaries and the veins. The blood enters the human heart through the arteries and after which the purification process takes place in which the bad blood is pumped into the heart through the veins and pure blood is pumped out.