An image of a man's chest is overlain
by a cutaway showing the lungs
and covered heart between.
If we looked inside the chest cavity,
we would see the lungs
and pericardium,
which is the fibrous covering
of the heart.
The camera moves in for a close-up.
The pericardium is removed
giving a clear view of the beating heart.
We could also see the heart beating.
The camera moves in tighter.
Two blood vessels run lengthwise
across it,
one on the left
the other on the right.
Smaller vessels branch from them.
Here are the left and right coronary arteries.
They supply blood
to specific regions of the heart.
If either is damaged or blocked,
it could injure the heart wall.
A cutaway of a small section of artery
shows red blood cells flowing through it.
In a healthy artery,
red blood cells flow through unimpeded.
A small section of the wall appears damaged.
Tiny yellow beads of plaque
begin clinging to it,
forming a solid clump that extends
part way across the artery.
But if the inner wall is damaged,
cholesterol plaque can build up.
This progressively narrows the space
through which blood flows.
A blood clot flows toward the clump and becomes part of it.
Eventually,
the artery may become too narrow
for clotted blood to pass through.
If it does,
the artery could become completely blocked.
Red blood cells pile on top the blockage.
The image returns to the heart.
That would cause a lack of oxygen,
or ischemia,
in the part of the heart
the artery supplies.
Heart muscle is red,
but a section in the lower right pulses
and turns blue.
The result is a heart attack,
known as a myocardial infarction.