Feedback Mechanism PDF

FEEDBACK MECHANISM  When you eat, your body absorbs the glucose, a carbohydrate, in your food. But what happens to your body when you ingest too much carbohydrates?. How about when you skip a meal?  Your body has built in mechanism that allows it to function normally. All you...

FEEDBACK MECHANISM  When you eat, your body absorbs the glucose, a carbohydrate, in your food. But what happens to your body when you ingest too much carbohydrates?. How about when you skip a meal?  Your body has built in mechanism that allows it to function normally. All your body system are regulated by feedback mechanisms the serve to maintain balance. Homeostasis refers to the body’s ability to maintain a constant internal environment. This is important because it allows your body to function well in spite of the ever-changing external environment.  Homeostasis It helps the cells in your body to function optimally. All cellular activities are controlled by different feedback mechanism that regulate body temperature, body fluids, gas concentration, blood pressure, and glucose concentration. It enables your body to balance it’s internal conditions despite the changes in the environment that you cannot control.  Homeostasis through Positive and Negative Feedback Mechanisms For the body to maintain it’s healthy state, it’s cells and body organs should operate at their optimum level. Any changes in the external environment may affect the body’s internal environment, witch will cause the body to continually adjust. To do so, your body can work through positive and negative feedback mechanism.  The stimulus response model shows the events that happen when a certain stimulus changes the internal condition of the body. The following is a brief definition of a stimulus response model. Stimulus – it is structure that produce the change Receptor – a structure that detects the change Control center – a structure that determines the appropriate response to the stimulus Effector – can be organs, glands, tissues that are instructed to adjust the amount output that produces a desired effect. Response – the outcome of the adjustment that should remove the initial stimulus  The Negative Feedback Mechanism This type of mechanism allows the internal condition of the body to go back to it’s normal or ideal state by inhibiting or removing the stimulus. As the concentration of products or substances inside the body increases, the rate of process decreases.  The Positive Feedback Mechanism The positive feedback mechanism is the exact opposite of the negative feedback mechanism. Here, the increase in the concentration of products or substances also results in an increase in the rate of process. Positive feedback mechanism allows the output to enhance the original stimulus  Regulation of Body Temperature Your body needs to maintain a relatively constant internal temperature for metabolic process proceeds efficiently. If the internal temperature of your body changes, your body will find ways to maintain it’s temperature. If your temperature is high it will cause imbalance in the body. Thus,, the heat-loss center in the hypothalamus signals the sweat glands to secrete sweat. The sweat in your body is vaporized by your body heat to lower your internal body temperature. Once your body temperature decreases or when you cool down, the heat- loss center in the hypothalamus shuts off. This heat loss protects the body from excessively high temperatures  On the other hand, when the environment or your body temperature fall, the heat promoting center in the hypothalamus is activated this allows your skeletal muscles to start shivering. Shivering occurs to help your muscles generate heat. When the body temperature finally increases or when you feel warmer, the hypothalamus is triggered to shutdown the heat promoting center.  Regulation of Body Fluids Water needs to be regulated in our body. It is continually released form our body through sweat and urine. When water is lost, dissolved solutes become concentrated in the cells, thus creating high osmotic pressure. This change is detected by the osmoreceptors in the hypothalamus, the hypothalamus sends a message to the nerves to activate the drinking centre and the posterior pituitary gland to release the antidiuretic hormone (ADH).  Also, once the (ADH) reaches the kidney, the kidney will decrease the amount of water to be excreted in the urine and increase the amount of water to put back into the blood stream. This process will go on until the hypothalamus detects the amount of water in the blood is normal. Thus water intake and increased reabsorption of water in you kidneys helps maintain the normal amount of water in your body  Regulation of gas concentration Carbon dioxide and oxygen are two important gases that must have normal concentration inside the body. The respiratory system helps in maintaining the concentration of these two gases. It also maintains the pH level inside your body. Both oxygen and carbon dioxide enters and exits the lungs and travel through the bloodstream. Oxygen is important for cellular respiration because a constant supply of this gas contains homeostasis, also carbon dioxide should also be at constant concentration inside the cell. If the carbon dioxide level is not carefully manage, it would accumulate at problematic levels.  Regulation of Blood Pressure The circulatory system is a very important body system because it does not only control the temperature, body fluids, and gases it also regulates blood pressure. Blood Pressure is the pressure exerted by the blood against the walls of the blood vessels. Blood pressure keeps the blood from flowing through all the blood vessels so that the cells receive oxygen and nutrients, witch are important to sustain life. If the blood pressure reaches too high, it can damage the blood vessels, however if the blood pressure is too low, the organs in your body will not receive adequate oxygen and nutrients.  If there are stimuli that can cause the increase or decrease of blood pressure, the nervous helps in regulating it. Blood pressure is closely monitored by baroreceptors that send messages to the cardio regulatory center of your medulla oblongata witch is found in the walls of blood cells. As baroreceptors detects changes in blood pressure, they transmit the information to the brain. The brain responds by initiating mechanism that bring blood pressure back to normal. Baroreceptors will send signals that cause vasodilation. Vasodilation allows the peripheral resistance of blood to decrease.  The opposite happens when the baroreceptors detect a drop of blood pressure. A low blood pressure causes decrease in the signals sent to the cardio regulatory center of your medulla oblongata. The sinoatrial node (SA node), witch is responsible for creating nerve impulses, would fire more frequently to increase heart rate. When the heart is stimulated to increase pumping force, the blood pressure increases.  Regulation of Glucose Concentration Glucose is an important sugar in the body. When combined with oxygen inside the cell, it produces the energy necessary to perform certain psychological processes. Many functions in the body are based on energy based from glucose. Without glucose metabolic reactions would not occur. Therefore glucose should be regulated as too much or too less of it might result in brains damage.  Hormones such as insulin and glucagon play important roles in regulating glucose levels in the body allowing the glucose level to increase and decrease, respectively. Changes in blood glucose level are perceived by the islets of langerhans in the pancreas.. The islets of Langerhans are cells that release insulin and glucagon. With the presence of insulin, cell membrane in the bloodstream become more permeable to glucose. Insulin and glucagon have contrasting and antagonistic effects. Insulin inhibits the increase of glucose in the blood, whereas glucagon promotes it’s production, their counteracting effects help maintain homeostasis in the blood glucose level THA NK YOU