1) The Role of the public transportation agency (PTA) (i.e. Blood circulation system) in maintaining homeostasis: –
كيف تقوم الدورة الدموية بالحفاظ على توازن البيئة الداخلية في دولة جسم الانسان
To know how any system maintains homeostasis, we need to know 2 things: –
- Its function
- The factors that make this system or organ succeed in its function
How the circulation system contributes in the automated coordination system to maintain the homeostasis?
The function of any public transportation system in any country is transporting anything including people. However, in the country of the human body, the transportation system doesn’t transport people (cells) but it transports nutrients to them and take the wastes to get rid of it through the drainage system (the kidneys). The only cells or persons that are transported by the public transportation system is the POLICE and ARMY soldiers (i.e. Cells of the immunity system) to search for invaders (microbes or antigens) and protect citizens (cells) and the country agencies (organs).
What does make the blood circulatory system or the public transportation system succeed in this function?
2 things can make the blood circulatory system or the public transportation agency (PTA) succeeds in their function: –
- The way by which the extracellular fluid is transported.
- The structure of the tunnels of the transporting system (i.e. the blood vessels of the blood circulatory system)
1) The way by which the extracellular fluid is transported: –
The blood circulatory system transports the extracellular fluid in 2 stages: –
- Stage one: – transport of blood or the extracellular fluid to and through all the body parts in the blood vessels even to the smallest capillaries (the smallest districts) that reach small tissue of cells (small groups of people live in small districts or group). In this stage:
- The extracellular fluids carry nutrients to all the people.
- Blood circulate all the tunnels or the blood vessels once per minute at rest and as many as six times per minute at the extreme activity.
- Stage Two: – movement of the extracellular fluid between the blood capillaries (or small tunnels in the small districts) and the intercellular spaces (or the interstitial spaces) which is spaces between the tissue cells. The interstitial spaces are the exchange zones, in which, continual exchange of the extracellular fluid occurs to provide nutrients and take the wastes away (i.e. the people takes food and get rid of their wastes). Actually, this exchange occurs between the blood plasma and the interstitial fluid that fills the intracellular spaces (interstitial spaces) between cells or people (NOTE that the interstitial fluid is the extracellular fluid found between cells).
In small words, in stage one, the transporting system sends the food to people and in stage two, it gives the people the food and takes the wastes away. This is done every minute at rest and as many as six times at extreme activity.
2) The structure of the tunnels of the transporting system (i.e. the blood vessels of the blood circulatory system): –
2 important things in the structure of the public transportation system: –
1) The too small openings in the small tunnels or capillaries.
- The walls of the small tunnels, in the small districts, contain very small openings that are permeable to most molecules and nutrients found in the plasma which is the extracellular fluid found in blood vessels) and impermeable to the large protein molecules.
- The predominant presence of these very small openings allows easy continual diffusion (which occur by the kinetic motion) of extracellular fluid to the interstitial spaces carrying shipments of the nutrients and ions to unload in the interstitial spaces and take wastes away back to the blood (or to the tunnels of the transportation system). If this continual diffusion doesn’t exist, the circulation of blood within one minute will not be useful.
2) The distance between the tunnels or blood vessels and cells or people: –
- There is a 50-micrometer distance between the capillaries or the small tunnels or the small blood vessels and the cells that are directly found near these capillaries or smallest tunnels.
- This distance can be considered as the place of exchange in which people or cells leave their wastes and from which the extracellular fluid takes the wastes away and replace it with nutrient packages in few seconds. This ensures the diffusion of any substance from the blood to the interstitial spaces between the cells within a few seconds.
- This ensures continual mixing of the extracellular fluid of blood plasma and the extracellular fluid between the cells (i.e. in the interstitial spaces) and hence complete homogeneity of the extracellular fluid and this leads to the constant internal environment throughout the body.
So, making homogeneity between the extracellular fluid in plasma and the interstitial spaces maintain homeostasis. The circulatory system is able to do this role because it has the ability to do that where its capillaries has too small openings that allow passage for extracellular fluid carrying the ions and the small molecules of nutrients and allow continual diffusions of the extracellular fluid from blood to the intestinal spaces which ensure continual exchange of the nutrients and the wastes. The circulating system also allows for space for exchange between the capillaries and the cells which ensure diffusion of any substance needed by the cells and continual mixing between the extracellular fluid in the blood and in the intestinal spaces which cause homogeneity of the extracellular fluid which means constant internal environment and this is homeostasis.
Now, we know briefly the role of the transportation system in homeostasis. Actually, it is the most important agency in this coordination system or physiology. IMAGINE, in real life, if there is no transportation system in your country, what will happen? People will not be able to get food which leads to death and methods to get rid of the wastes will not be available leading to waste accumulation, which causes diseases that lead to death too. However, you can live with one kidney, you can live without a spleen, your defense agency can be stopped and you will still have weak defenses. In other words, if any errors occur in some organs or agencies, you can remove part or the entire organ and continue your life (the country still found) but without blood or the heart that pumps blood (or can be considered the engine for the transportation system), you are dead.