The circulatory system is made up of the vessels and the muscles that help and control the flow of the blood around the body. This process is called circulation. The main parts of the system are the heart, arteries, capillaries and veins.
As blood begins to circulate, it leaves the heart from the left ventricle and goes into the aorta. The aorta is the largest artery in the body. The blood leaving the aorta is full of oxygen. This is important for the cells in the brain and the body to do their work. The oxygen rich blood travels throughout the body in its system of arteries into the smallest arterioles.
On its way back to the heart, the blood travels through a system of veins. As it reaches the lungs, the carbon dioxide (a waste product) is removed from the blood and replace with fresh oxygen that we have inhaled through the lungs.
Functions of Parts of the Human Circulatory System
This system consists of the following-
1) Blood- The blood mainly consists of plasma and three kinds of solid particles called formed elements. The plasma mainly consists of water but it also contains some proteins, minerals and other substances. The three formed elements are the red blood cells, the white blood cells and platelets.
2) Blood vessels- These form a complex network throughout the body to help transport the blood. They are of three types. The arteries, the veins and the capillaries.
3) Heart- This is a muscular organ situated in our chest. It is responsible for pumping the blood through the blood vessels.
Vital Functions of the Circulatory System
The circulatory system performs a lot of vital functions. They are as follows-
1) Respiration- The red blood cells contain a compound called haemoglobin that can carry oxygen and transport it to the body parts via circulation and carries carbon dioxide back to the lungs. During this process the blood follows two different routes through the heart called systemic circulation and pulmonary circulation to separate the oxygenated and deoxygenated blood.
2) Nutrition- The circulatory system carries digested food substances to the cells for providing energy to the body and also for storage. These nutrients enter the blood stream through the thin walls of the intestines into the cappilaries and are carried to the liver. The liver removes some nutrients and stores the rest for use later. The blood that leaves the liver contains nutrients that the cells use for energy production.
3) Carrier of hormones- The blood also transports hormones that are produced by various glands throughout the body. These hormones then cause various changes in the body involving growth and reproduction.
4) Removal of wastes-The circulatory system also helps the body to dispose off wastes that would otherwise get accumulated. The wastes include carbon dioxide, ammonia, salts, etc. The liver converts ammonia and various other useless substances that enter through the digestive system and converts them into water soluble substances that are then carried by the blood to the kidneys for removal.
5) Protection from diseases- The white blood cells engulf and destroy bacteria, viruses and other harmful substances that enter the body. The platelets in the blood help in clotting of the blood in injuries so that an excess of blood is not lost.
6) Maintaining body temperature- Blood circulation maintains the body temperature and keeps it stable by absorbing the heat coming from the cell's energy production.
Functions of Circulatory System
The functions performed by the circulatory system in all animals are
1) Transport of nutrients like glucose, amino acids, vitamins, minerals
2) Transport of oxygen from the organs of respiration to the body cells.
3) Transport of carbon dioxide from the body cells to the exterior.
4) Transportation of nitrogenous wastes from the body cells to the organs of excretion.
5) Transportation of hormones from the endocrine glands to their specific target organs.
6) Transportation of water, hydrogen ions and chemical substances all over the body for their uniform distribution.
7) Transportation of heat from one region to another for homoeothermy.
8) Transportation of intermediate metabolites from one part of the body to another.
Importance and Functions of Circulatory system
The importance and functions of circulatory system are as follows:
Circulatory system is the one system through which all of the other systems are connected. It is connected with the respiratory system, the digestive system excretory system etc. Every cell in the body depends on this system for its proper functioning.
It has an important role in the immune system of the body since White Blood Cells (leucocytes) defending the body against infective organisms or foreign substances. Erythrocytes (or Red blood cells) carry oxygen through out the body, collect carbon dioxide and transport it back to lungs.
The circulatory system is essential for the exchange of substances such as nutrients, waste products and respiratory gases with the environment. It is responsible for the continuous supply of oxygen and nutrients to the cells and removes metabolic wastes.
The circulatory system delivers blood to the organs and all the other parts of the body including hands, legs, brain, etc... It delivers Pure (Oxygenated blood) to all pars of the body and receives Impure (Deoxygenated blood) from them and delivers them back to heart, heart is the pumping organ which pumps the blood to all parts of the body, and also it's the main part of Circulatory system.
The survival of the developing embryo depends on the circulation of blood to maintain homeostasis and a favorable cellular environment. Homeostasis is the self-regulating mechanisms by which biological systems such as blood pressure, body temperature, acid-base balance etc… maintain a stable internal condition in the face of changes in the external environment.
Types of Circulatory System
The vertebrates including Human beings have a closed circulatory system and in such a circulatory system the blood circulates through the blood vessels, and chemicals are exchanged by diffusion. In contrast, arthropods, such as insects and spiders, have an open circulatory system, in which there is no blood vessels to carry blood, the blood is pumped by the heart and then flows through the body cavity, directly bathing the internal organs.
