The heart is divided into four chambers - the right and left atria on top which receive blood and the right and left ventricles below which pump blood out. The atria and ventricles are separated by valves which allow blood to flow in only one direction. The right side receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it out to the body. Valves prevent backflow through the heart's chambers and vessels.

1. ANATOMY OF HEART

2. ANATOMY OF HEART
The inside of the heart is divided into right and
left side with the help of vertical septum.
Each side is subdivided into an upper chamber
and a lower chamber by a valve.
The upper chambers are called atria and lower
chambers are called ventricles.
The valves between the atria and ventricles
help the blood to flow in single direction.

3. The valve that separates right atrium from
right ventricle is called tricuspid valve and it has
3 flaps or 3 cusps.
Similarly, the valve that separates left atrium
from left ventricle is called bicuspid valve and it
has 2 flaps or 2 cusps.
The ventricular valves have little muscle
projections of papillary muscles.

4. The two largest veins of the body, the superior
and inferior vena cava empty the contents into
the right atrium.
From the left ventricle arises the aorta which
carries the oxygenated blood to various parts of
the body.
From the right ventricle arises the pulmonary
artery which carries deoxygenated blood from
heart to the lungs for oxygenation.

5. The opening of aorta is guarded by the aortic
valve and the opening of pulmonary artery is
guarded by pulmonary semilunar valve.
The aortic valve prevents the return of blood
from aorta into the ventricle and pulmonary
valve prevents the return of blood from
pulmonary artery to the right ventricle.
The heart is supplied with arterial blood by the
right and left coronary arteries. The venous
return of blood is by coronary sinus that
empties into right atrium.