There are two possible definitions for the term end organ. It can refer to the terminal ends of sensory nerve cells, where this part of the nerve cell is bound around the ends of the nerve fibers. End organ may also refer to damage that various organs, such as the kidneys or liver, sustain from an illness that affects another part of the body. End organ damage is often the cause of death in conditions such as hypertension.
The end organ of a nerve cell is found at the terminal end of a sensory nerve. These specialized cells contain fibers that sense pressure, temperature, texture, and pain. There are also cells known as sensory neurons which are sensitive to information collected by the eyes, ears, tongue, and nose. Nerve fibers that collect sensory information are bound together in the end organ of these sensory nerves and neurons.
Unlike other types of nerve cells, the ends of sensory nerves and neurons do not line up with the dendrites of another nerve cell. Instead of an axon terminal, these nerve cells have fibers which allow the nerves to collect information from the different sensory organs. The end organ of a nerve cell binds all of these fibers together. Once sensory data is collected, this information travels through the nerve into the central nervous system, where it is analyzed and processed.
Alternatively, the term may apply to an organ in the body that is damaged by a disease. In most cases, the end organ is damaged by a condition that originated in another organ or system. Hypertension, for example, is a condition that directly affects the heart and circulatory system. The blood vessels lead to various organs, however, which can become damaged by the increased pressure on the arterial walls. The kidney can be an end organ damaged by hypertension, as can the brain, if the patient has a stroke.
Human Immunodeficiency Virus (HIV) and Acquired Immune Deficiency Syndrome (AIDS) are diseases that commonly result in end organ damage as well. The disease itself attacks the immune system, but the damage to the immune system can lead to a number of different problems. End organ damage from HIV/AIDS is often the cause of death.