HUMAN CIRCULATORY SYSTEM

Heart is muscular blood pumping organ. It is located at the centre near the chest. It is the size of our clenched fist. Human’s heart is enclosed in a sack called pericardium. The pericardium is made up of thin layer protecting the heart.

The heart is made up of four chambers. The chambers at the upper part (right and left side) of the heart are called auricles. Meanwhile the two chambers at the lower part are called ventricles.

The right and left side of the heart are separated by septum. The function of the septum is to prevent the mixing of oxgenated blood (rich in oxygen) and deoxygenated blood ( poor in oxygen).

PATHWAY OF BLOOD

1. Deoxygenated blood enters right atrium through superior and interior vena cava.


2. Blood from the right atrium then through right ventricle.


3. The deoxygenated blood flows into pulmonary artery and then brought to the lungs.


4. From the lungs, oxygenated blood flows into pulmonary vein and into left atrium.


5. From the left atrium the oxygenated blood then moves into left ventricle.


6. Then passes into the aorta to go to the rest of the body.