Question

angina pectoris is chest pain caused by reduced
multiple choice
stimulation of the myocardium.
blood supply to cardiac muscle.
fluid in the pericardial sac.
contractility of the heart.
action potentials from sa node.

Explanation:

Angina pectoris is chest pain due to reduced blood - supply to the cardiac muscle. When the blood supply to the heart muscle (myocardium) is insufficient, it can't get enough oxygen, causing pain. Other options are not the direct cause of angina. Stimulation of the myocardium is not the main cause, fluid in the pericardial sac is related to pericardial conditions, contractility of the heart is not the cause of angina pain, and action potentials from the SA node are related to heart rhythm, not angina pain.

Answer:

blood supply to cardiac muscle.