The muscle helps to transport blood to and from the heart
The heart is primarily responsible for pumping blood throughout the body, and the muscle that enables it to do so is cardiac muscle, which is specialized for continuous, rhythmic contractions. The heart itself is a muscle, made up of four chambers: two atria (upper chambers) and two ventricles (lower chambers). These chambers work in a coordinated manner to pump oxygen-rich blood to the body and oxygen-poor blood to the lungs.
In addition to the heart, the vascular system plays a critical role in the transport of blood. The arteries, arterioles, capillaries, venules, and veins form a network through which blood circulates. The arteries and arterioles take blood away from the heart, and the veins and venules bring blood back to the heart.
While the heart does the main work of pumping blood, it is not the only muscle involved in blood circulation. The skeletal muscles also assist with blood flow, especially in the veins. When skeletal muscles contract, they compress the veins that run through or near them, helping to push the blood in the veins towards the heart. This is often referred to as the "muscle pump," and it is particularly important in preventing blood from pooling in the lower extremities when a person is standing or walking.
One-way valves in the veins prevent backflow of blood and ensure that it moves in the correct direction back to the heart, complementing the action of the muscle pump provided by skeletal muscle contractions.
It is important to note that while skeletal muscles assist in venous blood flow, the primary muscle that creates the force needed to circulate blood is the cardiac muscle of the heart.