The Heart

The muscular organ known as the heart serves as the body's circulatory pump and is roughly the same size as a closed fist. As a result, the heart receives deoxygenated blood through the veins and sends it to the lungs for oxygenation before pumping it to other arteries. The thoracic cavity, which is posterior to the sternum and medial to the lungs, is where this organ is located. The aorta, pulmonary veins and arteries, and vena cava are then joined to the heart's base (Lewis, 2016). The apex rests superior to the diaphragm. The base is located to the midline of the body where the apex points towards the left. Therefore, almost 2/3 of the mass of the heart exists on the body's left side while 1/3 is located towards the right.
Importance
The heart is important in the human body because it helps in the circulation of blood through systemic circuit and pulmonary circuit. The pulmonary circuit involves the movement of the deoxygenated blood from the right ventricle through the pulmonary artery to the lungs where it gets back to the heart as oxygenated via the left atrium through the pulmonary vein (Hall, 2011). The systemic circuit entails the movement of the oxygenated blood through the left ventricle to the aorta where it enters the capillaries and arteries. As such, the body tissues are supplied with oxygen. The blood that is deoxygenated then returns through the veins to the vena cava by entering the heart via the right atrium. Furthermore, the heart also functions as a muscle and needs fresh oxygen and nutrients supply.
Tissue types
The heart comprises of different tissues that include the cardiac muscle, connective tissue, and the nervous tissue, and the blood. The blood acts as the main collection of all the cells. The cardiac muscle tissue is specialized as the pumping mechanism for the blood in the entire body. It forms the bulk of the heart mass and is only found in the heart. The cardiac muscle has high endurance and contractile strength, which makes it to function without rest in the entire lifetime. The nervous tissue helps in the electrochemical signals propagation in the form of the nerve impulse. The connective tissues bind the organs and the cells of the body and offer the integration, support, and protection.
Cell types
The heart is comprised of different cell types that include myocytes, which act as the specialized muscle cells. These can contract even in the absence of the nerves stimulation. The sinus node presents in the right atrium play the role of producing the electrical impulses that assists in the contraction of the myocytes. These myocytes form the myocardium, which is the thick muscular layer of the heart.
The interior of the heart surface is made of the endocardium, which consists of the endothelial cells referred to as the skin cells (Hall, 2011). These cells assist in sealing the heart and ensuring that there is connectivity to the blood vessels. The cells prevent leaks and filter gases, fluids, and molecules that move out and into the cells. The pericardium is the double-layered and thin sac cell surrounding the heart. Such plays the role of protecting the heart from external contaminants.
The cell-types work together by having connectivity among themselves and being specialized on their independent tasks. As such, there are electrochemical signals, which are sending from one cell to another to activate its functionality. These ensure that the cells support the entire function of the organ.
Different cells are needed in the body because each cell performs an independent function. As such, the organization and collaboration of different units of the cells helps in achieving a great goal on the functionality of the organ. The specialization of the cells also helps in producing the outmost good in terms of performance.





References
Hall, J. (2011). Guyton and Hall textbook of medical physiology (12th Ed). Philadelphia, Pa.:
Saunders/Elsevier.
Lewis, T. (2016). Human heart: Anatomy, function & facts. Retrieved from:
https://www.livescience.com/34655-human-heart.html