Three tissue layers called tunicae, or coats, surround the lumen of an artery. The adventitia (outer coat) is the outermost layer of an arterial wall and is composed of connective tissue containing elastic fibers and another layer of protein called the external basement membrane. Smooth muscle cells comprise the tunica media, or middle coat. The muscle cells contract or relax to constrict or dilate the artery.

See also Coronary Angiogram, Angiography, Angioplasty, and Cardiac Catheterization.

An angiogram is an x-ray examination of the arteries (arteriogram) and veins (venogram) to detect blockage or narrowing of vessels.

See also Adventitia and Ischemia.

Cardiology is a medicine sector that covers the clinical study, treatment and imaging of the heart actions and diseases.

See also Ischemia, Calcium Score, Cardiac Phase, Diastole, Adventitia, Defibrillator, ECG Trigger, Arrhythmia Rejection.