FUNCTIONS AND COMPONENTS OF THE CIRCULATORY SYSTEM

The human body is a complex structure which has many organs, or systems with different essential tasks. Human beings need oxygen to live, so they have respiratory system that helps them absorb oxygen and release carbon dioxide when they breathe. But these gases can’t circulate in the human body without support. Therefore, we need the circulatory system to help us transport these gases. Furthermore, this system also helps to transport nutrients, metabolic wastes and regulate body temperature. Similar to other organ systems in our body, the circulatory system also has many different components and functions.
The first component of the circulatory system is the cardiovascular system. It includes two main parts_the heart and blood vessels. The human heart is different from animals’ because it is four-chambered. It pumps blood to the lungs and body cells through blood vessels. A heart of an adult human can pump about 5 liters of blood per minute. Blood vessels have two types. The vessels that carry blood away from the heart are called arteries. They bring blood to the lungs and then combine oxygen with hemoglobin, which is why blood is bright red. Another type of blood vessel is the veins that carry blood from the lungs to the heart. The blood, distributed by these veins is called venous blood. It’s darker red because it contains less oxygen. The second component is lymphatic system that consists of lymphatic vessels and lymphoid tissues. It transports tissue fluid and absorbed fat from the intestine back to the blood and its white cells also support the immune system.
Functions of the circulatory system are different from other organ systems in the human body. According to Stuart Ira Fox, the functions can be divided into three areas. The first is transportation including respiratory, nutritive and excretory function. Red blood cells, or “erythrocytes”, are important for respiration because “oxygen from the inhaled air attaches to hemoglobin molecules within the erythrocytes and is transported to the cells for aerobic respiration”(Fox, 364). Carbon dioxide produced by cell respiration is eliminated when we breathe. In addition, the system also transports nutrients throughout our body. Blood vessels are responsible to absorb the mechanical and chemical breakdown of food and carry these products to cells and every part of the body. Another function is excretion that expels ions, water and other molecules as wastes from metabolism of the human body. The second area is regulation. The system transports the hormone by blood to help our body, especially other systems. The circulatory system also keeps our body temperature at 37 degrees Celsius(98.6 degrees Fahrenheit). Temperature regulation, which makes our body temperature cooler when it is hot or warmer when it is cold, is aided by the diversion of blood. The third area is protection that helps reduce bleeding by clotting. The system also has “leukocytes” known as white cells which protect against many disease-causing agents. When certain substances such as viruses are put into the body, these cells will produce in the blood many antibodies that can fight disease.
The circulatory system is very important for our human life. It helps our body transport nutrients, gases and metabolic wastes. But today, there are many factors which can harm our circulatory system, especially the heart such as alcohol, fat in food etc, so we need to protect our health by doing exercise and eating more fruits and vegetable. These things are very good for our body, especially our circulatory system.
Fox, Stuart Ira. “Heart and Circulation.” Human Physiology. WCB/McGraw-Hill, 1999.