Homeostasis refers to any self-regulating process by which biological systems attempt to maintain stability despite changes in the external and internal environment (Sturmberg & Martin, 2013). Biological systems interact with each other to maintain a suitable condition of the internal environment for the survival of the living organism. The biological systems of the living organism are in a state of constant change.
The regulation of the systems within a given range of various conditions helps to keep the living organisms alive and healthy. The systems also interact with the external environment in different ways. The conditions of the external environment change widely in an unpredictable way. The biological systems respond to these changes in a manner that helps to maintain the conditions of the internal environment. In this case, the systems use the effector, receptor, and centre control mechanisms. The receptor detects changes in the internal environment and sends signals to the control center. The control center, in turn, processes the signal and determines whether the changes detected are within the range acceptable for the survival of the organism or not. It then sends signals to the effector to initiate an appropriate response to the changes.
Homeostasis maintains the conditions of the internal environment within a given range rather than at set points (Sadava, 2009). This phenomenon is necessary because maintaining the internal environment at set points would make it difficult for an organism to survive since the external environment, which affects the internal environment, changes widely in an unpredictable manner. Therefore, the biological systems have to be maintained within a given range to adapt to various changes that occur over a wide range and short period in the external environment. The body temperature, for instance, is maintained at around 98.6 Fahrenheit. If the body temperature were set at 98.6 Fahrenheit such that the body would not survive under any deviation from this temperature, people would not survive. In this case, while the biological systems would only operate at a specific set temperature condition, the external environment would not. The body would not be able to adjust to changes in temperature of the external environment. Consequently, the possibility for survival in the environment with ever changing temperature would be significantly compromised.
Hormones are molecular chemical messengers that are synthesized by cells in one part of the body but are secreted by glands to the circulation from where they get to another part of the body where they cause changes (Awang, 2009). Hormones play a significant role in the homeostatic processes in the body. In this case, different hormones regulate different processes and different conditions of the internal environment. Insulin and thyroxin are some of the hormones that take part in homeostatic processes of the body systems. Insulin is produced in the pancreatic cells called islets of Langerhans. On the other hand, thyroxin is produced by the thyroid gland.
The synthesis of thyroxin hormone occurs in the follicular cells of the thyroid gland. There are three steps involved in the synthesis of thyroxin. The first step involves the import of iodine into the follicular cell. Since the concentration of iodine inside the follicular cells is higher than it is outside the cells, iodine is imported into the cell through active transport. In the next step, tyrosine gets iodinated. In the thyroid cells, tyrosine is found in the thyroglobulin is a protein and is found in the lumen of the of the thyroid cell. Thyroglobulin is made of both amino acid and carbohydrate molecules. Among the amino acids constituting thyroglobulin are the 140 tyrosine molecules. Out of these molecules, only about two or three get converted to T4 or T3. Tyrosine gets iodinated while still attached to the thyroglobulin. Thyroid peroxidase enzyme is responsible for catalyzing the iodination process. In the third step, thyroid-stimulating hormone (TSH) stimulates the release of thyroxin hormone from the thyroglobulin.
Insulin is responsible for the regulation of blood glucose. Usually, the level of glucose in the blood increases after meals. The body has a mechanism for ensuring that blood glucose level is maintained within a narrow range. In general, insulin regulates the level of glucose in blood by facilitating the absorption of glucose from the bloodstream into the cells. In other words, insulin acts like the key that unlocks the cells to allow glucose molecules to enter the cells. However, the mechanism is not as simple as it sounds. Rather, the hormone regulates the blood glucose levels through various mechanisms. Insulin mainly acts on fat cells, liver cells, and muscle cells. Other than facilitating the uptake of glucose by the cells from the bloodstream, the hormone does the following: stimulating the cells of the liver and muscles to make proteins, stimulating the cells of the liver and muscles to store to convert glucose into glycogen for storage, and preventing the kidney and liver cells from making glucose from other compounds in the process known as gluconeogenesis. Through these mechanisms, insulin prevents the release of glucose into the blood stream. Consequently, it prevents the increase in blood glucose level.
The secretion of insulin into the bloodstream is triggered by an increase in the level of blood glucose level. The more the blood glucose level increases, the more the amount of insulin released becomes. In normal people, the level of blood glucose should not rise beyond 120mg/dl two hours after the meal. Blood glucose level peaks two hours after the meal. Blood glucose level that is greater than 120mg/dl recorded 2 hours after a meal is an indication of hyperglycemia. Continuous occurrence of hyperglycemia is an indication of diabetes. Diabetes is a condition characterized by the inability to regulate blood glucose level. It is partly caused by the impairment of insulin synthesis or secretion.
Thyroxin regulates the basal metabolic rate of the body. It does so by increasing the activity and number of mitochondria in the cells. By increasing the body’s metabolic rate, thyroxine helps control the body’s temperature. During low-temperature conditions, there is the need for the body to produce heat energy to raise the temperature. Therefore, the body promotes metabolic activities that produce more heat energy. The actions of thyroxin are important during cold weather. Thyroxin also ensures that the body’s metabolic activities take place at a suitable pace.
If the two hormones, insulin, and thyroxin are disrupted, the body would lose its ability to regulate blood glucose level and the temperature within the required range respectively. Concerning the level of glucose in blood, it would not be possible for the systems of the body to keep the level of glucose in blood below 120mg/dl if insulin is disrupted. Consequently, the level of glucose would go beyond this limit as much as possible. Secondly, the cells would be starved of glucose since the uptake of glucose would be impaired. Many complications would also result from the disruption of insulin. Such complications include neuropathy, retinopathy, and hyperglycemia. If thyroxin is disrupted, the body would encounter many complications. First, the body will lose its ability to regulate the temperature. Therefore, it would not be possible for the affected people to survive under cold weather conditions. Secondly, it would not be possible for the body to keep metabolic activities at the required pace.
Homeostasis gives human beings independence in surviving in the environment. Without it, the human being would have to rely exclusively on the environment for survival. Indeed, there would be absolutely nothing that people would be able to do without a favorable condition of the external environment. For instance, if there were no homeostasis, people would only be able to survive under the normal temperature which is 98.6 Fahrenheit. It means that people would have to devise means to ensure that the external environment is maintained at 98.6 Fahrenheit so that they can go about their businesses. It would only be possible for people to go outdoors if the temperature stays at 98.6 Fahrenheit.
Homeostasis also gives the human being the ability to detect changes in the environment and respond appropriately. In this case, through mechanisms of the receptor, control mechanism, and effector, people are able to detect unfavorable environmental conditions and respond to them appropriately. For example, water is an essential component of the body. Indeed, it plays a significant role in supporting different body functions. Therefore, a certain level of water must be maintained in the body for survival. When the level of water in the body is too low, dehydration occurs. Dehydration can lead the damaging of the kidney, shock, and even organ failure. The body detects low water level and respond by inducing the feeling of thirst. Consequently, one is prompted to take water to relieve the feeling. In general, if the biological systems were not able to self-regulate in a manner that helps the living organism to survive in the environment with ever changing conditions, the functioning of the body would be affected in several ways.
The maintenance of homeostasis is very important at the fetal stage of human development. Indeed, it is at this stage that efforts should be made to ensure that the pregnant mother stays within the normal range of all conditions as much as possible. Changes in the external environment influence the conditions of the internal environment. For instance, an increase in temperature causes the body to sweat in an attempt to maintain a temperature within the normal range. If a pregnant mother is exposed to harsh conditions of the external environment, her internal environment is affected negatively. The internal environment of the other, in turn, affects that of the fetus. As the mother’s systems adjust to the changes in the external environment, the foetal systems adjust too. Any disruption of homeostasis may be fatal to the developing fetus and the mother. Indeed, some effects of this disruption may affect the fetus in its subsequent stages of development. For instance, there is the need for the blood sugar level to be maintained within the normal range during pregnancy. If a pregnant mother records high blood glucose level continuously for a relatively long period, the fetus may develop diabetes in its subsequent stages of development. Once born with the condition, one cannot be treated. Therefore, the condition is like a life sentence.
Homeostasis is a key factor to the survival of the living organisms in the environment. Indeed, without homeostatic functions of the biological systems, the body would cease to function. Homeostasis is the key factor supporting the interaction between the body and the environment.
References
Awang, D. V. (2009). Tyler's herbs of choice: the therapeutic use of phytomedicinals. CRC Press. P.151
Sadava, D. E., Hillis, D. M., Heller, H. C., & Berenbaum, M. (2009). Life: the science of biology (Vol. 2). Macmillan.
Sturmberg, J. P., & Martin, C. M. (2013). Handbook of systems and complexity in health. New York: Springer. p.162Bottom of Form
