The heart can refer to as a complex muscle that pumps blood through the three divisions of the circulatory system like the coronary (vessels that serve the heart), pulmonary (heart and lungs), and systemic (systems of the body). Coronary circulation intrinsic to the heart does take the blood directly from the main artery (aorta) coming from the heart. For pulmonary and systemic circulation, the heart must pump blood to the lungs and the rest of the body, respectively. The heart primarily made of a thick muscle layer, called the myocardium, surrounded by membranes. It is one-way valves separate the four chambers. Blood vessels of the coronary system, including the coronary arteries and veins, give the heart muscles oxygen. The heart help in the circulatory system that is movement of the blood around the body,
The Heart Layers
The heart is made of three layers which are the epicardium, the myocardium, and the endocardium. The inner wall of the heart is covered by the endocardium. The myocardium comprises of the heart muscle cells which make up the middle layer and the bulk of the heart wall. The outer layer of cells is known as the epicardium, the second layer of which is a membranous layered structure that surrounds and protects the heart; it permits enough room for vigorous pumping, but also keeps the heart in place, decreasing friction between the heart and other structures.
The Blood Vessels
The heart has its own blood vessels that give the heart muscle with blood. The coronary arteries branch from the aorta, encamping the outer surface of the heart like a crown. They separate into capillaries from where the heart muscle is taking oxygen before converging again into the coronary veins to return the deoxygenated blood back to the right atrium, where the blood is re-oxygenated through the pulmonary circuit.
Atherosclerosis is the barrier of an artery by the buildup of fatty plaques. The heart muscle will not survive without a steady supply of blood; because of the narrow size of the coronary arteries and their role in serving the heart itself, atherosclerosis can be deadly in these arteries. The slowing of blood circulation and subsequent oxygen deprivation may cause severe pain, known as angina. Complete blockage of the arteries can cause myocardial infarction—the death of cardiac muscle tissue—which is commonly referred to as a heart attack.