The
heart is about the size of your fist and is
located behind your chest bone, a little left
of the center.
It is made up of muscles
and its main purpose is to pump blood, filled
with oxygen to the organs and tissues, throughout
the body.
The heart has 4 chambers.
The upper 2 chambers are called the right atrium
and left atrium. The lower 2 chambers are the
right and left ventricle, and have thick muscular
walls.
To pump the blood
the left ventricle contracts, and each time it
does this it is considered one heart beat. The
heart usually beats between 60-90 times per minute,
also called the pulse rate.
The heart also needs
blood and oxygen, which it gets from the coronary
arteries. There are 2 main coronary arteries,
the left and right coronary artery
The left main coronary
artery divides into 2 branches-the left anterior
descending artery and the left circumflex artery.
