Final answer:
The tissue that lines the coronary arteries is called endothelium. It plays an active role in regulating the contraction of the heart muscle and can contribute to clot formation and cardiovascular disease if damaged.
Step-by-step explanation:
The tissue that lines the coronary arteries is called endothelium. The endothelium is a simple squamous epithelium that is continuous with the endothelial lining of the blood vessels. It plays an active role in regulating the contraction of the muscle within the heart and also regulates the growth patterns of cardiac muscle cells. Damage to this endothelial lining can cause clot formation and contribute to hypertension and cardiovascular disease.