Muscular activity requires a source of energy. When muscles are working aerobically, three main products are created: heat, carbon dioxide, and water. The heat produced by active muscles helps to maintain body temperature, so muscle is contributing to heat homeostasis. However, if more heat is being produced than is needed, as for example during vigorous exercise, the excess heat has to be lost from the body to prevent a harmful rise in body temperature. Therefore, homeostasis helps by controlling the bodies physical output and the stress that is put upon muscles, which keeps the muscles from being overworked.
All systems must have homeostasis to maintain stability and to survive. Homeostasis is so important because it can allow an animal to adapt to a changing environment. The body attempts to maintain a constant level of physical output to achieve homeostasis. However, it can only work within its limits, where extreme conditions can disable the negative feedback mechanism.
In humans, the process is a little different. It involves a constant monitoring of lots of different factors. An example of one of the factors it monitors is the gases oxygen and carbon dioxide. The concentrations of these substances in body fluid remain unchanged, despite changes in the external environment.
The body can regulate its internal environment through feedback systems. A feedback system is a cycle of events in which the condition of the body is monitored, changed, re-monitored and re-evaluated. Each monitored variable such as temperature, blood glucose and blood pressure is termed as a controlled condition. Any disruption that changes a controlled condition is called a stimulus. Only three components make up the feed back system - a receptor, a control center and an effecter.
Receptor - is a body structure that monitors changes in a controlled condition and sends input in the form of nerve impulses to the control center
Control center - a control center in the body sets the range of values within which a controlled condition should be maintained
Effecter - is a body structure which receives output from the control center and produces a response that changes the controlled condition.
In order for a control system to function there must be receptors to monitor changes n the internal environment. These receptors send information to a control center which monitors the change and integrates the information. The control center then sends information to effectors which generate a response to the change in the internal environment.
The group of effecters communicating with their control center forms a feedback system that can regulate the controlled condition in the body's internal environment. Feed back systems can either form positive or negative systems.
Negative feedback system: In negative feedback a change in the internal environment is monitored by the receptor and transmitted to the control center. The control center then evaluates the input and if necessary issues a output command to an effecter generating a response which cancels the effect of the stimulus and re-establishes the homeostatic condition.
Positive feedback system: This system tends to strengthen or reinforce a change in one of the body's controlled condition. A change in the homeostatic condition is detected by receptors and the information is transmitted to the control center. The control center activates effectors which generate a response.
