The focus of the circulatory system is the heart---- the chief pumping tool composed of muscle; the left side of the heart has two linked compartments
i.e. the left atrium and the left ventricle. The right side of the heart also
has two associated compartments i.e. the right atrium and the right ventricle. The right
and left sides of the heart work collectively. Blood moves in the heart via two large veins
referred to as the inferior and superior vena cava, pouring oxygen-deficient
blood from the body into the right atrium.
The pulmonary vein pours blood (laden with oxygen) from
the lungs into the left atrium. Blood moves from the right atrium into the
right ventricle via the open tricuspid valve and moves from the left atrium
into the left ventricle through the open mitral valve. Blood departs from the
heart via the pulmonic valve, into the pulmonary artery and to the lungs. Blood
departs from the heart through the aortic valve, into the aorta and to the
body. This procedure happens in a recurrent manner, affecting blood to pour constantly
to the heart, lungs and body.