 |
| Blood Circulation |
FUNCTIONS OF BLOOD CIRCULATION
Circulation function is to serve the needs of the network; for transporting nutrients to the network, for transporting products that are not useful to the body, to deliver the hormone from one organ to the other organs, and in general to maintain a suitable environment in all tissue fluids of the body in order to survive optimally, as well as to the metabolic functions of the body's cells.
BLOOD VESSEL
The blood circulation in the human body has a special channel that is known as the blood vessels. Broadly speaking there are two kinds of blood vessels, the veins and arteries, but each vein is divided into several types of blood vessels according to the size and function.
1. arteries
A blood vessel that transports blood under high pressure through tissue. Arteries have a strong vascular wall, and in it the blood flowing at high speed.2. arterioles
Is the smallest branch of the arterial system and serves as a control valve, which will be released into the blood capillaries. Arterioles also has a strong muscular wall is capable of closing arterioles altogether or allow it to dilate, so as to have the ability to regulate blood flow to the capillaries as a response to the needs of the network.3. Capillary
Serves for the exchange of fluids, nutrients, electrolytes, hormones, and other substances between blood with interstitial fluid. For this role, the capillary walls are very thin and permeable to small molecular substances.4. venules
Serves to collect blood from capillaries. Venules are branches of the smallest veins and will gradually be merged into the vein that the larger size.5. Vena
Veins are blood vessels that transports blood from the heart to all body tissues. As important as the arteries, veins act as the main reservoir of blood. The difference is, the vein system has a very low pressure and has a layer of thinner walls. Nevertheless, the walls of veins have muscles that can cause the veins to contract (vasoconstriction / venous lumen becomes narrower) and also can dilate (vasodilation). Thus vein serve as a container of extra blood that can be controlled depending on the needs of the body.CLASSIFICATION AND MECHANISM OF CIRCULATION
Circulation in the human body is divided into two: Circulation Systemic and Pulmonary Circulation. Systemic Circulation is the circulation supplying blood to the entire body except the lungs, while the pulmonary circulation is the circulation that supplies blood to the lungs to exchange oxygen with carbon dioxide gas.
The process begins with the Systemic Circulation of the blood flow throughout the body's tissues to the Vena Cava Superior and Inferior Vena Cava, through the veins of blood will be entered into the Heart Right Atrium and then through the tricuspid valve into the Right Ventricle Heart. The process followed by the Pulmonary Circulation, blood which has been deposited in the right ventricle to the lungs to be pumped before passing through the pulmonary artery. In the lung tissue is to be a process of diffusion of gases, ie the exchange between oxygen gas with carbon dioxide, in which the carbon dioxide is released to exhaled out of the body through exhalasi (exhale) and oxygen obtained from inhaled (breathed) will be bound by the erythrocyte / cell red blood for distribution to the body's cells. The process followed by the Systemic Circulation again, in which blood from the lungs (oxygen-rich) will come out of the lungs and into the left atrium through the pulmonary veins Heart, then the blood will pass through the mitral valve and into the left heart ventricle. Blood deposited in the left ventricle was pumped into the aorta (the largest artery in the human body) to be distributed to all body tissues. Blood flow in the arteries will experience gas diffusion in the target organ and the process occurs within the structure of capillary blood vessels contained in the target organ. After experiencing the gas diffusion in capillaries, the blood will enter venules (small veins) which in turn will continue to flow into the veins of the body to be accommodated back into Vena Cava and the process that I described in the beginning was going to happen again. And so on because this process will never stop as long as humans live.
GAS DIFFUSION
Organ pulmonary alveoli have a structure that plays an important role in the breathing process because there alveoli capillary blood vessels for the diffusion process of oxygen gas / O2 from the alveoli into the pulmonary capillaries and diffusion of carbon dioxide / CO2 from the blood into the alveoli of the lungs.
All gas-related respiratory physiology is the simple molecules that can move independently of one another, this process is called diffusion. This diffusion process occurs through a membrane around the terminal portion of the lungs, not only in the alveoli itself. These membranes are together known as breathing membrane or membranes surrounding the lungs that has several layers, among others: (1) coating liquid that coats the alveoli and contain surfactants to reduce the surface pressure fluid alveoli, (2) alveolar epithelial consisting of epithelial cells thin, (3) the epithelial basement membrane, (4) the interstitial space between the thin alveolar epithelial and capillary membrane, (5) capillary basement membrane which in some places are united with epithelial basement membrane, and (6) the capillary endothelial membrane. Despite the many layers, but the thickness of the respiratory membrane is very thin. The average diameter of the pulmonary capillaries are also very small, so the membrane eritosit / red blood cells in it can be in direct contact with the walls of capillaries, causing O2 and CO2 do not need to go through a large number of plasma when diffuses between alveoli and erythrocytes so as to increase the rate of diffusion the.
Figure (a) above shows the process of diffusion of O2 and CO2 that occur in the lungs:
O2 from the alveoli penetrate the respiratory membrane and into the pulmonary capillaries to bind to hemoglobin in erythrocytes, formed a bond called Oxyhemoglobin. While CO2 from the plasma to penetrate the capillaries and into the pulmonary alveoli, then CO2 will be issued through the expiratory breathing process.
Figure (b) above indicates the process of diffusion of O2 and CO2 that occur in the network:
Oxyhemoglobin bond in erythrocytes will be separated so that O2 would be out of erythrocytes and penetrate the capillary wall to get into the tissue cells. While CO2 from tissue cells will go into the capillary and binds to the compound H2O / water in the plasma.