Bulb, from the latin bulbus is a biological structure that has the shape of a light bulb (or an onion). The term admits of many uses and applications, with reference, for example, to the body for storage of nutrients in some plants.
In anatomy, the concept is used to refer to the medulla oblongata, also known as the elongated marrow. It is a segment of the stem of the brain that lies between the bridge (Pons) and the foramen of the skull.
The medulla oblongata, which borders the spinal cord, which can be considered as its prolongation has the shape of a truncated the lower Summit cone. You can see a front (with a longitudinal Groove), a side and a rear (with a demi-posterieure Groove).
Another division of the medulla oblongata segments it in the pyramidal decussation, the Sensory decussation and an upper part where bulbar olives.
Among the functions of the medulla oblongata, it is necessary to mention the transmission of impulses from the spinal cord to the brain and control of activities respiratory, digestive (gastrointestinal), cardiac and vasoconstrictor. The transmission of impulses occurs of different fibres nerve, also well rising than falling.
The medulla oblongata regulates the secretion of digestive juices and responds to the reflex functions such as swallowing, coughing, sneezing and vomiting, among many others.
It should be noted that damage to the medulla oblongata are fatal, causing sudden death by respiratory arrest or cardiac (or cardio) arrest.