Homeostasis is a process that ensures a steady state of equilibrium in an organism at all times. This is brought about by regulating many variables such as fluid balance, temperature, concentrations of various ions such as sodium and potassium.
However, aspiring medical students need to understand what is homeostasis in much greater detail and explore the factors responsible for it. Homeostasis is usually brought about by a natural resistance to change when the body is already in optimal conditions. It brings about the change through a regulatory mechanism that controls various aspects of the body. The components of the regulatory mechanism include receptors, effectors and a control centre.
The receptor is the component responsible for sensing changes in the environment. Receptors are of two types, namely – thermoreceptor, mechanoreceptors. The control centre sets an acceptable maintenance range (such as body temperature). The effectors are cells that act on the impulses sent from the control centre. It brings back the body to a state of equilibrium.
For example, a drop in the ambient temperature can make the body lose heat. The body prevents losing excess heat through vasoconstriction – where blood supply is rerouted from the extremities of the body with large surface areas (such as the skin). This effectively reduces blood flow and helps with retaining heat. The metabolic rate is also increased – which helps with heat generation. This is further followed by shivering, which brings about thermogenesis (a process of heat generation)
Another example of homeostasis is blood glucose regulation. When the blood sugar levels fall very low, glucagon from the pancreas is released to promote the production of glucose. Similarly, insulin is produced from the pancreas in response to an elevated blood sugar level after a meal.
Failure of homeostatic mechanisms can bring about specific diseases. A well-known homeostatic disease is diabetes mellitus. Here, the blood glucose levels are unable to be regulated by the body, resulting in hyperglycemia.
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