السبت، 30 يناير 2016

HEART ATTACK
Heart Attacks and Heart Disease
More than a million Americans have heart attacks each year. A heart attack, or myocardial infarction (MI), is permanent damage to the heart muscle. "Myo" means muscle, "cardial" refers to the heart, and "infarction" means death of tissue due to lack of blood supply.
What Happens During a Heart Attack?
The heart muscle requires a constant supply of oxygen-rich blood to nourish it. The coronary arteries provide the heart with this critical blood supply. If you have coronary artery disease, those arteries become narrow and blood cannot flow as well as they should. Fatty matter, calcium, proteins, and inflammatory cells build up within the arteries to form plaques of different sizes. The plaque deposits are hard on the outside and soft and mushy on the inside.
When the plaque is hard, the outer shell cracks (plaque rupture), platelets (disc-shaped particles in the blood that aid clotting) come to the area, and blood clots form around the plaque. If a blood clot totally blocks the artery, the heart muscle becomes "starved" for oxygen. Within a short time, death of heart muscle cells occurs, causing permanent damage. This is a heart attack. 

ليست هناك تعليقات:

إرسال تعليق