Homeostatic Mechanisms and Malfunctions Leading to Disorders - Essay Example

? Homeostatic Mechanisms and Malfunctions Leading to Disorders First Homeostatic Mechanisms and Malfunctions Leading to Disorders The internal bodily environment is made up of physiological variables such as body temperature, blood sugar levels and mineral concentrations yet organisms are required to function effectively in this wide range of conditions. Homeostasis is the ability of systems or organism to be able to regulate their internal environment and maintain a stable constant condition in a changing environment by the release of hormones into the blood stream. Homeostasis is maintained by mechanisms in the body and all organs and tissues of the body carry out different functions aimed at maintaining constant conditions in the internal environment. Homeostasis is a mechanism by which the body maintains its own internal state of equilibrium even when there are changes in the external environment. This mechanism ensures that the body maintains a relatively stable state. The way this mechanism works can be described is a bit like the way a thermostat in a house or car engine cooling system works. When the temperature rises to a certain point then that triggers the switch for lowering the temperature which then blows cooler air into the environment. As soon as a particular desired lower temperature is reached then that triggers the switch to go to the off mode. Conversely, when the temperature goes lower to a predetermined level that triggers the switching on of the heater which then raises the temperature to the required level and switches off automatically once that pre-determined temperature is reached. The body has a similar mechanism that controls the state of certain bodily functions such as temperature. When the external environment temperature rises then that triggers a response from the control centre which in this case is the hypothalamus and that triggers the body to react to the rise in temperature by sweating, the activation of the capillaries on the skin and the urge to drink something cooling. Other reactions to bring the body temperature back to the stable required rate would be removing layers of clothing. Conversely when the temperature goes down then the control centre triggers a reaction that includes the increasing of metabolic action thus increasing the internal body temperature, the closing of the sweat pores reducing the loss of heat from the body through the skin and the reduction of the urge to drink something cold possibly even an urge to drink or imbibe a hot drink to raise the temperature back to a desired stable state. Homeostasis is an important body balancing mechanism that ensures that the stable steady state is maintained. An absence of this balance in the body is what causes stress which leads to a disorder or disease. Homeostasis is a mechanism that comes into play when the body regulates its temperature, the amount of water or other fluids in the body, the intake of glucose and other nutrients and a myriad other similar bodily functions. The illustration below explains the homeostasis process in a much clearer way. Figure 1. Homeostasis explained (Shmoop Editorial Team 2008). In the illustration above, as soon there is a change or imbalance in the state of the body (stimulus), the change is detected by the receptor which immediately alerts the control centre via the afferent pathway. The control centre then sends information along the afferent pathway to the effector which then influences the magnitude of the stimulus to bring the body back to a state of balance. Homeostatic control mechanisms work as a system made up of three components that depend on one another to control a particular physiological variable. The three interdepend components are the receptor, a control centre and an effectors. The receptor receives a stimulus and sends it to the control centre which sets the range at which the variable should be maintained and determines the appropriate response to particular stimuli. In most mechanisms the brain usually acts as the control centre. The control centre then sends the response to the effectors and after the response is received is when a change occurs to correct the deviation by either a positive or negative feedback. A negative feedback occurs when an increase in the variable that is being regulated causes a response that moves the variable in the direction opposite to the change. For example if there is an increase in blood pressure, as soon as the receptors in the blood vessels detect it they relay a signal to the brain which then sends messages to the heart and the blood vessels. The heart decreases the rate at which blood is being pumped while the blood vessels increase in diameter, causing the blood pressure to fall back to a desired lower level or point. If a negative feedback fails to achieve the desired response then the stress persists, leading to a disease. Negative Feedback Illustrated In negative feedback any change in stimulus is detected by the sensor which alerts the control or integrating centre which then causes an effector to reverse the stimulus. In this example the rise in blood pressure is detected as a result of which the brain signals the heart to decrease its rate resulting in a decrease in the heart rate which lowers the blood pressure Positive feedback occurs when the body responds by a reaction that intensifies or increases the reaction that is happening. For example, during childbirth, the act of the baby being released from the mother through birth canal contractions causes the increase in oxytocin hormone which then increases the intensity of the contractions and magnifies them, pushing the baby out with more “force” (Noel Ways n.d.). Whenever the homeostatic balance is upset, it results in disorders in the body which is what diseases are and if these imbalances are not corrected then the disease ravages the body which will eventually lead to death. In a normal functioning body for example, insulin is a hormone that is used by the body’s blood function system to detect and remove glucose from the body when the levels are too high. When glucose levels are too high, insulin triggers the removal of glucose from the bloodstream, until the normal balance is attained. When that balance is achieved then the expulsion of glucose stops. When a person has type I diabetes, their body is not able to produce enough insulin and is thus unable to regulate the amount of glucose in the blood. In type II diabetes the blood cells are unable to remove high concentrations of glucose from the blood. Thus in both these types of diabetes, the body is unable to maintain its homeostatic balance, which results in the range of diseases known as diabetes. This lack of balance ends up affecting multiple organs within the body. The central nervous system is affected to cause lethargy and stupor, which causes blurred vision. In the respiratory system this imbalance results in hyperventilation while in the gastric system it causes nausea, vomiting and abdominal pain. A combination of all these malfunctions results in general weight loss and health deterioration which, if unchecked, eventually leads to death (Shmoop Editorial Team 2008). When it comes to temperature regulation, a rise in the external temperature triggers a response from the peripheral heat receptors in the skin which then signal to the temperature control centre in the brain – the hypothalamus which activates the skin reaction of the skin capillaries dilating which lets out heat from the body and also activates the sweat glands which give off heat when sweat evaporates from the skin causing the skin temperature to cool down. When there is a lowering of the temperature then the hypothalamus signals the thyroid hormones which increase metabolic action and shuts down the skin capillaries and sweat glands. The increased metabolic activity results in a rise in the internal body temperature. When there is an imbalance in any of these mechanisms then the body cannot self-regulate its internal temperature and this can lead to diseases that affect the whole body and have adverse effects on the body in terms of either very high temperatures of very low temperatures (Richardson n.d.). Similarly the homeostatic mechanisms are used to regulate the water retained in the body in that when there is increased water build-up in the blood the hypothalamus which contains the osmoreceptor cells which secretes the ADH (antidiuretic hormone).This hormone controls the absorption of water from the blood into the body cells thus reducing the amount of water in the bloodstream. It also suppresses any need for drinking liquids and ensures that the person is not thirsty. The opposite happens when there is a lowering of the amount of water in the blood resulting in less absorption of water from the urine into the body. It also stimulates the thirst mechanism and makes a person take a lot of water which is then absorbed into the bloodstream and the equilibrium is restored. When any of these homeostatic processes malfunctions there will be either a build-up of water in the body which may cause oedema or there will be too little water in the body leading to dehydration and loss of energy (Millar and White n.d.). References Millar, N and White, I. (n.d.). Homeostasis. Available: http://www.biologymad.com/resources/A2%20Homeostasis.pdf. Last accessed 7th June 2013. Noel Ways. (n.d). Feedback Systems. Available: http://www.noelways.com/courses/Body%20in%20Health%20and%20Dis/Lectures/Lec_1_Intro/Feedback_Sys.pdf. Last accessed 7th June 2013. Richardson, M. (n.d.). HOMEOSTASIS & HYDRATION. Available: http://www.nanocal.com/homeostasis.htm. Last accessed 7th June 2013. Shmoop Editorial Team. (November 11, 2008).Homeostasis - Shmoop Biology. Available: http://www.shmoop.com/animal-movement/homeostasis.html Last accessed 7th June 2013. Read More