(Greek: within, inside, into, in, on, inner)
This procedure has transformed the management of, for example, gastrointestinal diseases.
In chest disease, fiberoptic bronchoscopy has now replaced the rigid wide-bore metal tube which was previously used for examination of the tracheo-bronchial tree.
Fiberoptic colonoscopy can visualize the entire length of the colon and it is now possible to biopsy polyps (any mass of tissue that bulges or projects outward or upward from a normal body surface level), or suspected carcinomas, and to perform polypectomy (surgical removal of a polyp).
In the human body, two systems control all physiologic processes. One of these systems is neurologic while the other is endocrine.
The nervous system exerts point-to-point control through nerves. Nervous control is electrochemical in nature and is rapid.
The endocrine system broadcasts its messages to essentially all cells by the secretion of hormones into the blood and extracellular fluids.
Like a radio broadcast, it requires a receiver to get the message. To receive endocrine messages, cells must bear a receptor for the hormone being broadcast in order to respond to it.
The nervous and endocrine systems often act together to regulate the physiologic processes of the human body and those interactions constitute neuroendocrinology.