Final answer:
A myocardial infarction, also known as a heart attack, occurs when a blockage in the coronary arteries causes a severe reduction or stoppage of blood flow to the heart, leading to the death of heart muscle tissue. This condition is often the result of a buildup of atherosclerotic plaque which can permanently damage the heart muscle, as cardiac muscle cells do not regenerate.
Step-by-step explanation:
A myocardial infarction, commonly known as a heart attack, occurs when the blood supply to the heart is severely reduced or stopped. This typically happens when a blockage occurs in the coronary arteries, which can result from the buildup of atherosclerotic plaque. These plaques are composed of lipids, cholesterol, fatty acids, and white blood cells like macrophages. If a portion of a plaque breaks off, it can travel through the coronary arteries and lodge in a smaller vessel, leading to a blockage that stops oxygen from reaching part of the heart muscle. Consequently, areas of the heart that depend on the blocked artery are starved of oxygen and begin to die.
The cardiac muscle tissue has a high demand for oxygen and can only survive a brief period without it. Without blood flow and the oxygen it carries, cardiac muscle fibers may die, resulting in irreversible damage to the heart muscle. Since cardiac muscle cells cannot be replaced, the effects of a myocardial infarction are permanent. Coronary heart disease, which can lead to myocardial infarction, is a leading cause of death in adults in the United States.