Humans have a double circulatory system- this means blood passes

The heart has

The top two chambers of the heart are called

The bottom two chambers of the heart are called

Blood flows from the lungs (rich in oxygen) to the heart in the

Blood flows from the lungs (rich in oxygen) to the heart into the

what prevents blood flowing from the ventricles back into the atrium when the ventricles contract

Blood is pumped out of the left ventricle (full of oxygen) at high pressure and passes to

Blood flows from the body (where the oxygen was used up to the right atrium in the

Blood is pumped out of the left ventricle (full of oxygen) at high pressure and passes into the

Blood ( with little oxygen) is pumped out of the right ventricle to the

The rate that the heart beats is controlled by a group of cells in the right atrium that act as a

Transport oxygen to the heart

Transport blood away from the heart

Blood flow at high pressure

Thick elastic walls to withstand high blood pressure

oxygen is transported in the

Have valves to prevent the blood flowing at low pressure from moving the wrong direction

Have bigger lumen (inside hole) to ease blood flow

Where does oxygen leave the blood and diffuse into the cells