Final answer:
The heart muscle receives its blood supply from the coronary arteries, which originate from the aorta and supply oxygen and nutrients to the heart's muscle cells.
Step-by-step explanation:
The heart muscle gets its blood supply from the coronary arteries. These arteries originate from the first portion of the aorta after it arises from the left ventricle. Specifically, the left posterior aortic sinus and the anterior aortic sinus give rise to the left and right coronary arteries, respectively. The coronary arteries branch into smaller arteries and finally into capillaries, which facilitate the exchange of oxygen and nutrients with the heart's muscle cells, or cardiomyocytes. Oxygen-depleted blood is then returned to the right atrium of the heart via the coronary veins. It's critical for the heart muscle to receive a consistent blood supply; without it, conditions such as atherosclerosis can lead to angina or myocardial infarction, also known as a heart attack.