Human Physiological Function And Homeostasis

Human Physiological Function And HomeostasisThe human being consists of trillions of cells all working together for the maintenance of the entire beingness. While cells may perform very divers(prenominal) functions, all the cells atomic number 18 quite similar in their metabolic requirements. Maintaining a constant native surround with all that the cells need to survive (oxygen, glucose, mineral ions, waste removal, and so forth) is necessary for the upbeat of individual cells and the well-being of the entire bole. The varied processes by which the body regulates its ingrained environment are collectively referred to as homeostasis.What is Homeostasis?Homeostasis in a factorral sense refers to stability, balance or equilibrium. It is the bodys attempt to maintain a constant internal environment. Maintaining a stable internal environment requires constant supervise and adjustments as conditions change. This adjusting of physiological schemes within the body is called homeos tatic linguistic rule.Homeostatic regulation involves three parts or instruments 1) the receptor, 2) the supremacy center and 3) the effector.The receptor receives selective information that or sothing in the environment is changing. The overtop center or integration center receives and processes information from the receptor. And lastly, the effector responds to the commands of the control center by either opposing or enhancing the stimulus. This is an ongoing process that continually works to unsex and maintain homeostasis. For example, in regulating body temperature there are temperature receptors in the skin, which communicate information to the brain, which is the control center, and the effector is our inventory vessels and sweat glands in our skin.Because the internal and external environments of the body are constantly changing and adjustments must be made continuously to stay at or near the set point, homeostasis dismiss be thought of as a dynamic equilibrium.Cell s depend on the body environment to rest and function. Homeostasis keeps the body environment under control and keeps the conditions right for cells to live and function. Without the right body conditions, certain processes (eg osmosis) and proteins (eg enzymes) lead not function properly.All organisms need some control on their internal environmental conditions in order to ensure that they will be able to survive. Since many of the metabolic reactions that occur within an organism depend on the use of enzymes or flat the use of diametric organisms such as prokaryotic bacteria, it is essential that the optimal conditions required for the functioning of that enzyme be provided. Homeostasis therefore, is the tendency of organisms to regulate and maintain relative internal stability, and involves, among other processes, the maintenance of a constant body temperature, glucose concentration, pH, osmotic pressure, oxygen level, and ion concentrations. The ability to maintain a const ant internal environment, with which we are most familiar, is that of a constant body temperature in homeothermic organisms. For example, the sightly body temperature of a humanThe appliances that regulate homeostasis operate by feedback mechanisms. Negative and confirming feedback mechanisms operate in living things. Negative feedback mechanisms reverse the direction of the change. This maintains the constant, quieten state and so represents homeostasis. Positive feedback, on the other hand, acts to change the variable even more in the direction in which it is changing. Thus, positive feedback is not a homeostatic mechanism.Temperature control is an example of a negative feedback homeostatic mechanism. The region of the brain called the hypothalamus monitors the human bodys temperature. novelty from the normal temperature of 98.6F (37C) triggers a response from the hypothalamus. The temperature can be lowered by activation of glands resourceful of sweating, or raised by signa lling muscles to shiver to produce heat.Homeostatic mechanisms are a fundamental diagnostic of living things. Without these mechanisms, facets of a body that need to be kept operating in a steady state, such as temperature, salinity, acidity, ductless gland levels, concentration of gases such as carbon dioxide, and the concentrations of nutrients, would become so crazy as to threaten the life of the organism. In a healthy body, homeostatic mechanisms operate automatically at different levels molecular, cellular, and at the level of the whole organism.At the molecular level, the activity controlled by one gene can be under regulatory control by another(prenominal) gene. At the cellular level, a well-studied homeostatic mechanism is contact inhibition, in which cells stop dividing when they begin to crowd in on to each one other. Cancer, in which a hallmark is the rampant growth and division of cells, is a condition where the homeostatic mechanism of contact inhibition is inopera tive or defective.At the whole organism level, a homeostatic mechanism is a vital part of birth. During labor, the contraction of the uterus causes the release of a hormone called oxytocin from the hypothalamus. The hormone increases contraction frequency, which in turn stimulates the release of more oxytocin. This increasing contraction cycle propels the fetus round off the birth canal and into the world. After birth, the oxytocin acts to contract the expanded uterus in order to minify bleeding, thereby maintaining the mothers blood volumeThe importance of homeostatic mechanisms to the well being of an organism is underscored by the consequences of their failure. For example, at body temperatures of 107F (42C), the negative feedback systems cease to function. The high temperature then acts to speed up the bodys chemistry, raising temperature even more. This, in turn, further accelerates body chemistry, causing a further rise in temperature. This cycle of positive feedback is leth al if not halted.Two hormones are responsible for controlling the concentration of glucose in the blood. These are insulin and glucagon. The draw illustrates the principle of negative feedback control in action involving blood/sugar levels.Pancreas ReceptorsThe receptors of the pancreas are responsible for monitoring glucose levels in the blood, since it is important in every cell for respiration.Two types of cell release two different hormones from the pancreas, insulin and glucagon. These hormones target the liver, one or the other depending on the glucose concentrationIn cases where glucose levels increase, less glucagon and more insulin is released by the pancreas and targets the liverIn cases where glucose levels decrease, less insulin and more glucagon is released by the pancreas and targets the liverThe LiverThe liver acts as a storehouse for animal starch, the storage form of glucose. When either of the above hormones target the liver, the following occursInsulin Insulin is released as a gist of an increase in glucose levels, and therefore parents the conversion of glucose into glycogen, where the excess glucose can be stored for a later involvement in the liverGlucagon Glucagon is released as a result of an decrease in glucose levels, and therefore promotes the conversion of glycogen into glucose, where the lack glucose can be compensated for by the new supply of glucose brought about from glycogenDiabetesDiabetes insipidus is a condition where excess urine is excreted caused by the sufferers inability to produce ADH and promote the retention of piddle.Diabetes Mellitus is another form of diabetes where the sufferer does not have the ability to produce sufficient insulin, meaning that glucose cannot be born-again into glycogen. Anyone who has this condition usually has to take injections of insulin after meals and snacks to maintain their storage of glucose needed in emergencies.Fight or FlightIn emergencies, adrenaline is released by the bod y to override the homeostatic control of glucose. This is done to promote the breakdown of glycogen into glucose to be used in the emergency. These emergencies are often known as battle or flight reactions.Adrenaline is secreted by the adrenal glands. The secretion of it leads to increased metabolism, breathing and heart rate. at a time the emergency is over, and adrenaline levels drop, the homeostatic controls are once again back in placeOsmoregulationOsmoregulation is the regulation of water concentrations in the bloodstream, effectively controlling the amount of water available for cells to absorb.The homeostatic control of water is as followsA change in water concentration leads to active via negative feedback controlOsmoreceptors that are capable of detecting water concentration are situated on the hypothalamus next to the circulatory systemThe hypothalamus sends chemical messages to the pituitary gland next to it.The pituitary gland secretes anti-diuretic hormone (ADH), whic h targets the kidney responsible for maintaining water levels.When the hormone reaches its target tissue, it alters the tubules of the kidney to become more / less permeable to waterIf more water is required in the blood stream, high concentrations of ADH make the tubules more permeable.If less water is required in the blood stream, low concentrations of ADH make the tubules less permeable.This is illustrated by the flow chart belowEvolutionary Adaptations in Water RegulationSome of the tutorial pages in the adaptation tutorial investigate some of the evolutionary adaptations that organisms have achieved through natural selection. This looks atWays in which both animals and plants can be remedy adapted to cope with extreme environments (desert or wetlands).These changes can be behavioural, physical or anatomical, and in some way promote water regulation.Both plant and animal adaptations are investigated