Homeostasis is the maintenance of relatively stable conditions within the body. This process, controlled through feedback systems, ensures that the body’s internal environment remains stable despite changes in the external environment. Feedback systems are composed of a receptor, a control center, and an effector. When one or more of the components do not function properly the body is placed in a state of homeostatic imbalance. This condition can range in severity, but if left untreated it can cause death. Two extremely common examples of homeostatic imbalance are hypertension and diabetes.
Hypertension, high blood pressure, is a condition in which the force exerted by blood as it presses against the walls of the blood vessels is high enough to risk damaging those vessels. In a normal system a rise in blood pressure triggers pressure sensitive nerve cells in certain blood vessels called baroreceptors to send impulses to the brain. The brain responds to these signals by sending impulses to the heart to decrease in rate and to the vessels to dilate. In this case the baroreceptors are the receptor, the brain is the control center, and the heart and vessels are the effector. A breakdown or malfunction in any one of these areas will cause a rise in blood pressure that requires medical intervention.
Diabetes is a condition in which the body no longer produces the insulin needed to carry glucose out of the blood stream. The pancreas, a major endocrine organ, contains special cell types, called endocrine cells, which cluster together in the islets of Langerhans and secrete insulin and glucagon, the first step in blood glucose regulation. After a meal, if the endocrine system is working in homeostatic balance, blood sugars rise and insulin prompts the cells to take up the glucose. Diabetes is classified as an endocrine system disorder because diabetes can be the result of three main hormonal inconsistencies. The first two homeostatic...
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