01+Homeostasis

Homeostasis Chapter One __**//Content Summary //**__ // Homeostasis is the ability of the human body to continuously compensate and interpret feedback in order to maintain a dynamic equilibrium. Three of the most interesting subtopics within homeostasis are negative feedback, positive feedback, and neural and endocrine regulation. //

//Homeostasis revolves and relies heavily on a concept known as the feedback loop. The body can sense even the slightest deviation from the set point. The set point is an average around which the body oscillates to and from, but never strays to far away. The body has specialized sensors, and when this deviation occurs it is recognized very quickly and dealt with accordingly. The sensor relays a signal to the integration center for further processing. Each integration center deals with one specialized subject, and this center could be the brain, spinal cord, a cell, or an endocrine gland. After the integration center receives the signal it then must interpret the signal and decide on the appropriate course of action. The next vital step for the integration center is to direct the responses of the effectors. The integration center causes increases or decreases in the effector in order to reverse the deviation from the set point. Effectors are often muscles or glands which can be anywhere in the body. One very good example of a negative feedback loop is the bodies’ regulation of temperature. Specialized neurons (sensors) located in the hypothalamus recognize when the bloods’ temperature rises to high above the set point. The neurons in turn relay the signal to different nerve centers (integration centers) around the body. These integration centers relay the signal once more to the blood vessels (effectors) near the skin. When these vessels dilate the heat is lost through the skin as the blood flows closer to the surface. If these actions are not adequate to restore the set point the brain then sends a signal to initiate sweating from the glands. The release of sweat, and then the evaporation of it causes a major cooling effect that can help the body recover. On the other hand when the temperature drops to far below the set point the body has an opposite attack. The signal is still received in the hypothalamus by the specialized neurons. This is where the change happens because instead of sending the signal to the blood vessels near the skin. The signal is instead sent to the cutaneous arteries. The effector (cutaneous arteries) then is ordered to constrict the blood and prevent it from reaching the surface, and in turn this retains the body heat and avoids any losses. A more drastic measure would be the body starting to shiver if the previous method is unsuccessful. The muscle vibrations release heat in order to get the body back to set point.// [|Source One] [|Source Two] Source Three (Physiology Book) [|Negative Feedback Diagram]

//Of course the opposite action to negative is positive, and in a positive feedback loop the body senses the change but instead of sending out signals to reverse it the body goes through actions to amplify the change. There are a few different examples that come to mind when referring to the beneficial aspects of positive feedback loops. Blood clotting is mainly due to the production of a specific enzyme, which forms the matrix of a blood clot. This also increases the amount of thrombin that is being sent to the wounded area as well. The enzyme contains a catalyst, and also accelerates the process as well. So in an ideal situation, the speed is increased and increased until the clot has formed and the bleeding stops. Although this is an example of a positive feedback loop, it was ultimately started by a negative feedback loop in the form of the blood. The bleeding is a negative, and the positive is the bleeding to form a clot to stop the bleeding.// [|Source]

//When it comes to the maintenance of Homeostasis there are two main tools the body uses, and those two are intrinsic and extrinsic factors. Intrinsic are those mechanisms that are already present in the cell and are acting on it from within. Extrinsic is basically the opposite, meaning that they act from outside the cell or organ. These organs are controlled by the nervous and endocrine systems. The nervous and endocrine systems may just in fact be two of the most important systems in the body because they control a majority of the organs. The endocrine system controls the organs by releasing chemicals called hormones that travel through the blood until they reach the intended organ. To eliminate confusion each organ that the endocrine system controls can only interpret one type of hormone. This stops the possibility of any organ receiving the wrong hormones because they cannot read them. So the intention of the hormone is always read the correct way because only the target organ can be on the receiving end. The nervous system innervates with the organs that it has control over with tiny fibers. These fibers can be stimulated to release an electrochemical impulse that alerts the organ to the current situation. Target organs receive electrochemical signals in order to help achieve homeostasis. The process classifies both the nervous and endocrine systems as the effectors of the homeostatic endeavors.// Source (Physiology Book)

//__** Application **__// //Every individual’s body, including mine, needs to maintain homeostasis in order to function properly and stay alive. In the field of nursing, the nurse’s goal is to maintain or restore the patient’s homeostasis. For example, when the body is invaded by a bacterial infection, the immune system initiates the reproduction of more white blood cells. A few white blood cells that our body produces are called B cells and T cells. B cells perform the function of producing antibodies to particular infectious microorganisms, while T cells are the ones that kill the infectious microorganisms. When the body struggles to overcome the infection that is when a nurse may administer an antibiotic. Antibiotics are used to help fight off the infection because they can put a halt to the growth of the bacteria. Therefore, when the body realizes that the bacteria had infiltrated, homeostasis kicks in to return the body to its equilibrium. As a nurse, it is their job to act upon these types of scenarios to make sure the patient is receiving the care that is needed to maintain or restore homeostasis.//

__//** Essential Questions **//__

//Negative feedback is when a sensor realizes that there has been a deviation in the set point. The sensor then sends a signal to the integration center, which interprets the signal and sends an effector to resolve the problem. Insulin reduces the amount of blood glucose. The effects of insulin lowering the blood glucose in turn lower the amount of insulin needed because the blood glucose has already been lowered to a controlled number. This process is called negative feedback inhibition.// //Insulin and other molecules need to be regulated because too much is bad, and to little is bad as well. We need a certain amount of blood glucose to enable our bodies to have energy and be active. On the other hand too much or to little can have very negative effects on the body. Insulin and other molecules can be dangerous in high amounts; the regulation of such molecules is very necessary. The ability to get rid of the extras, or order more to be made has a vital role in maintaining our body’s homeostasis.//