Function of Homeostasis in Human Biology The preservation of stability or constant condition in a biological system by means of automatic mechanisms that work against influences leaning towards disequilibria is Homeostasis. (Homeostasis {hohm-ee-oh-stay'-sis}) Homeostasis is the capacity of the body to preserve relative constancy and work even when severe changes occur in the external environment or in one part of the body. (Homeostasis: Toxiocology Tutor III) This is one of the most basic theories in modern biology and this commenced in the 19th century when the French physiologist Claude Bernard observed the consistency of chemical composition and physical properties of blood and other body fluids. He asserted that this arrangement of the milieu interieur was vital for the life of higher organisms. The 20th century American physiologist Walter B. Cannon invented the word homeostasis and he developed and expanded the concept of self-regulating mechanisms in living systems. (Homeostasis {hohm-ee-oh-stay'-sis}) The word homeostasis comes from the Greek words for same and steady. This term refers to the ways the body reacts to preserve a constant internal environment despite environmental differences and disorders. Both the mind/brain and the body are gifted with a large number of automatic mechanisms of feedback reserve that work against influences tending toward disequilibria. (Walter Cannon (1871-1945): Homeostatis)

Homeostatic systems exhibits certain properties: They are ultrastable; Their entire organization internal, structural, and functional, adds to the continuance of equilibrium; They are erratic which means that the end effect of a specific action often has the contrary effect to what was anticipated. (Walter Cannon (1871-1945): Homeostatis) At all levels of organization in living systems like the molecular, cellular, organismic and even populational levels, the homeostatic mechanisms work effectively. In complex organisms like humans, it involves continuous checking and controlling of several factors like the gases oxygen and carbon dioxide, nutrients, hormones, and organic and inorganic substances. In spite of the variations in the external environment, the intensity of these substances in body fluid stays unaffected. (Homeostasis {hohm-ee-oh-stay'-sis})

For the existence of a cell, homeostasis is necessary and each cell provides as part of body system to homeostasis. (Topic: Concepts and Themes of Human Physiology) Homeostasis relies on the body's incessantly working of many actions. Its main activities or functions are reacting to variation in the body's environment, exchanging materials between the environment and cells, metabolizing foods, and incorporating all of the body's miscellaneous activities. Over the years, the capacity of the body to do many of its functions changes slowly. Generally, the body performs its duties perfectly at both ends of life -- in infancy and old age. At childhood, body works effectively and efficiently. At late maturity and old age the reverse is true. Slowly they become less and less able and operational. They usually work with utmost efficiency and effectiveness at young adulthood. (Body Functions and Life Process) Homeostasis of Some Body Parameters is essential for Life. Homeostasis is the perseverance of body conditions in a stable steady state and the cells of the body need specific conditions to live and function. Some of the body parameters kept in a steady state: Body temperature is controlled close to 37 deg C. And Blood pH is kept at 7.4. Arterial blood pressure is retained around 120/80 mm Hg. (Lecture 21: Control of Physiological Functions: Homeostasis)

In human beings, many organs check homeostasis in the blood that gives fluid for all tissues. The kidney controls urea, pH and water concentration. The lungs control oxygen and carbon dioxide. The liver and the skin control temperature. The liver and the pancreas control the glucose levels in the blood. Body cells must be in ambiance where the conditions do not vary much and never reach tremendous that are harmful to them. The atmosphere of body cells inside the body are called internal environment. The function of homeostasis is to maintain this internal environment constant. Certain procedures are required to maintain things stable and these may be called homeostatic procedures. Conditions that are controlled by homeostasis are blood glucose level, temperature, water content of the body, and the amount of carbon dioxide and urea being carried by the blood. Body cells are enclosed and immersed in fluid. This fluid, which is the tissue fluid, is made from blood. This gives the cells mineral salts like glucose. As cells require glucose all the time as energy for respiration, the level of glucose must not be allowed to drop. If the level goes too high, it is also harmful. The hormone insulin helps keep...

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In human temperature the thermoregulatory center in the hypothalamus manages homeostasis. It gets input from two sets of thermo receptors: receptors in the hypothalamus itself check the temperature of the blood as it goes through the brain, and receptors in the skin check the external temperature. Both pieces of information are required so that the body can make suitable modifications. The thermoregulatory center propels signal to many different effectors to modify body temperature. The thermoregulatory center is a component of the autonomic nervous system, so the different reactions are all instinctive. The accurate reactions to high and low temperatures are given in the table below. It is to be noticed that some of the reactions to low temperature actually produce heat, while others just preserve heat. Likewise some of the reactions to cold vigorously cool the body down, while others just lessen heat production or transmit heat to the surface. Thus based on the internal and external temperatures, the body has a variety of reactions. (Homeostasis: www.biologymad.com/)

A chain of control mechanisms preserves Homeostasis, some working at the organ or tissue level and others centrally regulated. To preserve homeostasis, the body acts to an unusual change produced by a toxin, biological organism, or other stress and makes some modifications to counteract the change. The main components accountable for the perseverance of homeostasis are: An alteration in the environment like a pain, loss of blood or existence of a foreign chemical. The receptor, which is the location within the body finds or accepts the stimulus, feels the changes from normal, and gives hint to the control center. The control center is the operational point at which the signals are obtained, examined and decided. As it combines the signals and other information to find if a reaction is required and the nature of the reaction it is sometimes known as the integration center. (Homeostasis:Toxiocology Tutor III)

The effectors are the body location where a reaction is produced, which oppose the early stimulus and thus tries to preserve homeostasis and finally there are the feedback methods. The main central homeostatic controls are the nervous and endocrine systems. We are constantly disputed by physical and mental pressure, wound, and disease, any of which can hinder with homeostasis. When the body has lost its homeostasis, it may go out of control, into dysfunction, sickness, and even death. (Homeostasis: Toxiocology Tutor III) The non-functioning causes diseases and may even cause death. (Lecture 21: Control of Physiological Functions: Homeostasis) When there is a failure or trouble in homeostasis, it leads to diseases. The body does not work properly, when there is a failure in homeostasis. The effects can be either partial or extensive. A local disease is more or less limited to a particular part of the body. A system disease disturbs the whole body or affects certain organ systems. Based on the harshness and extent, the disease can be categorized. Severe disease happens suddenly and usually the duration is less. Persistent disease usually is less acute, form slowly, and is long-standing. (Chapter 1 Body Organization)

Homeostasis at the tissue, organ, organ system, and organism stages replicate the joint and harmonized actions of many cells. Each cell adds to preserving homeostasis. (Homeostasis: Toxiocology Tutor III) Thus whatsoever be the outside situation, the body manages it to remain within certain limits to preserve health and life. For example, body temperature must be kept stable. On a cold day, the body will preserve heat by contracting the blood vessels near the skin and directing blood flow to help internal organs. The body will expand the blood vessels near the skin and disperse body heat with perspiration on a hot day. Many other elements like blood gases, hormones and water must also be preserved within strict limits. This practice of preserving the healthy internal balance is called homeostasis. (Naturopathy) All the body's organ systems supply to homeostasis. Some like the respiratory, digestive, and urinary systems eliminate and/or insert substances to blood. Though hormones control it, the nervous system has the final control. The activities of the other system are controlled by the nervous and endocrine systems. (Chapter 1 Body Organization)

Homeostasis aids in discharge by eliminating injurious wastes from the organism. Three systems essential in excretion are the respiratory whereby lungs eliminate CO2 and water. Integumentary is whereby blood vessels in the skin expand to let more heat to escape. Sweat glands form sweat that pulls…