Circulatory System Functions and Parts Involved in Humans
With regards to its function, the blood circulatory system (or, more specifically, the cardiovascular system) is divided into three sub-systems, namely, coronary circulation system, pulmonary circulation system, and systemic circulation system.
Coronary system is made up of coronary arteries and veins, and forms a network of vessels across heart muscles. Pulmonary system, on the other hand, is assigned the duty of replacing the oxygen-lacking blood with oxygenated one and to continue the cycle without a single pause.
Systemic circulation is the largest component of cardiovascular system that is responsible for circulating blood throughout the body organs while reaching each cell with the help of arteries and veins.
Role in Gaseous Exchange
Blood flows through lungs touching the respiratory membranes where excess quantity of CO2 moves along the concentration gradient, crossing the membrane, and escaping out of the lungs. In the similar way, oxygen enters the blood stream which is then made available to all the cells of body.
Transportation Of Materials
The ‘to and fro’ movement of essential substances, like nutrients, metabolites, electrolytes, chemicals and finished products is one of the important circulatory system functions in humans. The minute food particles, absorbed from the lining of intestine, are dropped at the desired locations at individual cell level.
After reaching their destination, the bonds in dietary molecules are broken to release the trapped energy. This energy is then stored in the form of ATP (Adenosine Tri-Phosphate) which is known as the energy currency in the body.
Disposal Of Waste Products
The metabolic wastes are received from individual cells which, while flowing with blood through kidneys, are separated from it and discharged out of the body by urination.
For the accomplishment of such circulatory system functions, the excretory system organs are called for assistance. If toxins and other harmful substances are kept inside the body for longer durations, these will seriously interfere with healthy functioning human body and result in various disorders.
Role in Immunity
RBCs (White Blood Cells, e.g. Lymphocytes) in the blood are also considered parts of the immune system. They protect the body against disease causing agents. Whenever a microbe enters the body through inhalation or food or a wound, it is immediately surrounded by the cells of defense system and ultimately killed.
However, it is not possible for white blood cells to be always successful and sometimes, they themselves fall victim to deadly germs, bacteria or viruses as in the case of AIDS (Acquired Immuno-Deficiency Syndrome).
So, as a result, the immunity providing cells are themselves destroyed and body becomes vulnerable to the attack of a number of diseases, making the patient suffer from several fatal disorders simultaneously.
Neutralization of Toxins
Antibodies present in blood not only identify and kill viruses and bacteria, but also neutralize toxins and other foreign substances. So, when you contact poisons, by any means, they are converted into less harmful substances.
Sometimes, harmful chemicals are produced as a result of metabolic processes in the body which are dealt with in the same way and cannot do any harm to any cell, tissue, or different organs of the body.
Contribution to Homeostasis
Keeping stable internal environment against any extreme changes in the surroundings is very necessary for the normal execution of various body functions, including metabolism (catabolic and anabolic reactions) and activities of reproductive system, integumentary system, muscle system, digestive system, and so on.
The biological catalysts or enzymes that carry out and speed up these reactions are very sensitive to minute changes in heat, temperature and pH of the medium of their working and cannot carry on any activity with perfection. When the fluctuations are beyond the bearable limits, the enzymes are completely destroyed and disintegrated as they are capable of performing their task only under optimum conditions.
Pulmonary and systemic parts of the cardiovascular system play a great role in the regulation of optimum internal body environment. For example, in scorching heat, the blood diverts its flow more towards the vessels on the surface of body thus eliminating excessive heat, and in case of extreme coldness, circulation of blood is more focused to deeper and unexposed part of body in order to conserve heat and maintain homeostasis. In the very same way, other factors, like pH are controlled and kept within bearable limits.
Platelets, that are cell-like bodies, without nucleus in the centre, play a role in repairing and protecting damaged tissues. For this purpose, whenever there is an injury or damage to the walls of vessels, they quickly recognize and gather at the place, thus protecting and saving it against any further damage or infection of germs.