The medulla oblongata is a structure found in the brains of vertebrate animals, including humans. This structure controls a number of autonomic functions, including respiration and blood pressure, making it a very critical part of the brain. Damage to the medulla oblongata can be fatal, as the patient will be unable to breathe, swallow, or perform other basic motor functions without assistance. This structure is also believed to be the key to how general anesthesia works, as the anesthetics depress the medulla oblongata so that it cannot function as it normally would.
This region of the brain is located at the bottom of the brainstem, the structure which connects the brain and spinal cord. The medulla oblongata sits directly on top of the spinal cord, below the area of the brainstem known as the pons. In cross section, this region can be seen as a small bulge in the brain stem which is designed to accommodate a number of important nerves.
In addition to regulating breathing and blood pressure, the medulla oblongata is also involved with cardiac function, various bodily secretions, swallowing, and reflexes. The functions regulated by the medulla oblongata take place at all hours of the day without any need for input from the rest of the brain. The medulla oblongata is also involved in the response to certain stimuli, creating reflexive responses which are designed to keep the body functioning. The ability to respond automatically to certain stimuli is critical to survival, as is the independent regulation of necessary functions like breathing and swallowing.
People who experience brain damage can still have functioning bodies, as long as the medulla oblongata is working. Damage to the medulla oblongata can result in the need for a ventilator or other supportive equipment to keep the body working. Depending on the nature of the damage, it may be possible to recover, or the patient may be considered to be brain dead or in a persistent vegetative state from which there is no possibility of recovery. When life support is withdrawn, the body will cease to function.
A variety of drugs and medications can cause changes in the function of the medulla oblongata, which can sometimes result in physical states which resemble death. Opiates and alcohol can both cause dysfunction until the body is able to express these substances, and in cases of overdose, it is possible to die because this area of the brain is not able to function normally. Sedatives can cause similar effects, as can hypothermia and coma.