Question

1. What is the coronary circulation?

2. What are the three main branches of the left coronary artery (LCA)? Where are they located on the heart surface (e.g. what part of the heart do they service)?

3. What are the two main branches of the right coronary artery (RCA)? Where are they located on the heart surface?

4. (a) What is a myocardial infarction? (b) What is its cause?

5. What is the medical significance of anastomoses in the coronary arterial system?

6. When do the coronary arteries obtain the greatest amount of blood to supply the heart: during heart contraction or heart relaxation? ___________________________________

7. (a) What are the three major coronary veins that empty into the coronary sinus? (b) Where does the coronary sinus empty the blood?

Answer 1

Ans-1. Coronary circulation is a part of systemic circulatory system that provides blood to heart and drains the blood from the heart. The two coronary arteries, the right coronary artery and left coronary artery arise from the aorta and the deoxygenated blood is returned to the heart through coronary veins.

Ans-2. The three main branches of left coronary artery (LCA) are left anterior descending artery, circumflex artery and posterior descending artery.

(i). The left anterior descending artery (LAD) supplies blood to the front and bottom of the left ventricle and in front of the septum.

(ii). Circumflex artery supplies blood to the left atrium , side and back of the left ventricle.

(iii). Posterior descending artery branch supplies blood to the inferior aspect of the heart.

Ans-3. The two main branches of the right coronary artery are right posterior descending artery and acute marginal artery.

(i). The right marginal artery supplies the majority of myocardium of the right ventricle of the heart.

(ii). The right posterior descending artery supplies blood to the inferior of the heart.

Ans-4. a. Myocardial infarction is the blockage of flow of blood to the heart. It occurs when coronary artery, the artery which supplies blood to the heart gets blocked.

b. The most common cause of myocardial infarction is the future of atherosclerotic plaque on the artery supplying the heart i.e. the coronary artery. This sufficient blood will not reach the heart and leading to heart unable to perform its function.