A myocardial infarction affects which of the following blood vessels of the heart?
A.
Pulmonary
B.
Aorta
C.
Vena cava
D.
Coronary
The Correct answer and Explanation is:
The correct answer is:
D. Coronary
Explanation:
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow to a part of the heart muscle (myocardium) is blocked for a prolonged period, causing damage or death to that section of the heart muscle. The coronary arteries are the blood vessels responsible for supplying the heart muscle with oxygen-rich blood. When these arteries become blocked, typically by a blood clot forming on a ruptured atherosclerotic plaque, the heart muscle supplied by the affected artery becomes deprived of oxygen, leading to ischemia and infarction.
Understanding the Coronary Arteries
The coronary arteries branch off from the aorta, the main artery leaving the heart. There are two primary coronary arteries: the right coronary artery (RCA) and the left coronary artery (LCA). The LCA further divides into the left anterior descending artery (LAD) and the circumflex artery (LCx). These arteries and their branches supply specific regions of the heart muscle.
- Right Coronary Artery (RCA): Supplies blood to the right atrium, right ventricle, the bottom portion of both ventricles, and the back of the septum.
- Left Coronary Artery (LCA): Supplies blood to the left atrium, left ventricle, and the front of the septum.
- Left Anterior Descending (LAD): Supplies blood to the front and bottom of the left ventricle and the front of the septum.
- Circumflex (LCx): Supplies blood to the left atrium and the side and back of the left ventricle.
Why the Other Options Are Incorrect:
- A. Pulmonary Arteries/Veins: These vessels carry blood between the heart and the lungs. The pulmonary arteries transport deoxygenated blood from the right ventricle to the lungs, while the pulmonary veins carry oxygenated blood from the lungs to the left atrium. These vessels do not supply the heart muscle itself.
- B. Aorta: The aorta is the main artery that carries oxygenated blood from the left ventricle to the rest of the body. It is not directly involved in supplying the heart muscle with blood, although the coronary arteries branch off from the aorta.
- C. Vena Cava: The vena cava refers to two large veins (superior and inferior) that return deoxygenated blood from the body to the right atrium. They play no role in supplying blood to the heart muscle.
In summary, a myocardial infarction directly affects the coronary arteries, which are vital in providing the heart muscle with the oxygen and nutrients necessary for its function. Any blockage in these arteries can lead to severe and potentially life-threatening damage to the heart muscle.