The blood contains many components. The main component of blood is red
blood cells, they help carry oxygen. They have a very large surface area and
contain hemoglobin, which binds to the oxygen and also makes the blood
cell appear red.
The blood also has white blood cells. They are used for defense against
disease; they roam the body and ingest or engulf any foreign microorganisms.
Platelets in the blood help to clot the blood when there is an injury, which
prevents large blood loss The liquid that carries everything in the blood is
called plasma.Plasma is a pale straw-colored liquid and can contain molecules
such as glucose, carbon dioxide, urea, hormones etc.
When problem occur in the body and blood is lost, blood can be given to the
person through a blood transfusion to keep them alive.
If the arteries become blocked, then stents can be places within the arteries
to keep them open and prevent the artery becoming blocked.
If an artery becomes blocked, then blood will stop flowing to the heart and
therefore a heart attack will occur.