Medulla oblongata

The medulla oblongata (Latin for " medulla ") is the furthest below ( caudal ), this part of the brain and is part of the brainstem and thus to the central nervous system. It forms the Myelencephalon ( hindbrain ) and is also called the bulbus medullae spinalis or bulb cerebri. Together with the metencephalon ( hindbrain ) it is part of the rhombencephalon ( hindbrain ). The medulla oblongata is downward to the spinal cord is not sharply defined. By definition, it extends from the outlet of the first spinal nerve up to the bridge ( pons). Visible in cross-section the connecting line of the two halves is called raphe and mainly consists of intersecting nerve fibers.

In the medulla centers are located for the control of blood circulation, respiration, and for the sneezing, coughing, swallowing and sucking reflex and vomiting (see also vomiting center ). In the medulla oblongata are also biosensors that regulate, for example, the acid -base balance of the body. In addition, all nerves that connect the brain to the body through her run.

A failure of the medulla oblongata, eg by an injury of the cervical spine, usually leads to death. On the other hand, man can live on with the help of the medulla oblongata in spite of failure of a large part of the cerebrum ( brain death part ). Since there are the centers for breathing here, such a patient does not even have to be artificially ventilated. Patients are in a deep coma and are usually referred to as Apalliker.

Structure

The medulla oblongata is divided functionally into the following three sections: tegmental area ( " hood" ), Pyramis ( " Pyramid" ) and nuclei olivares ( " olive pits " or simply " olive "). The tegmentum is back, under the fourth ventricle of the brain in the vicinity of the fourth ventricle. In the tegmentum are the origins of various nerve cells, which are commonly referred to as core areas (eg cranial nerve nuclei or nuclei for the inhalation and exhalation, the " respiratory center ").

The two Pyramides (singular Pyramis ) are the long protrusions on the front. Here run the pyramidal tracts, the Nervenzellaxone from the cerebral cortex contain for muscle movement. A little further down you can see a connection between the two Pyramides, the decussation pyramidum ( pyramidal tract crossing). This is the place, pull on the approximately 80 % of the nerve axons to the other side.

The olives are the bulges slightly to the side of the Pyramides.

Between Pyramides and olives XII occurs. Cranial nerve ( hypoglossal nerve ) from. In the Olive many different types of neurons to come from the brain and from the spinal cord to " toggle " with their synapse to another neuron. The incoming neurons in the olive have different functions. More generally, the olive is to be regarded as a coordination center for muscle movements, especially for fine motor skills. Therefore, the most nerve fibers run from the olive to the cerebellum, because this is responsible for fine motor coordination of muscle movements. Also, information from the muscles on their current state of motion or its position ( proprioceptive sensibility ) end here in the olive, to then be forwarded to the cerebellum.

In the olive, there is a large nuclear complex. Within this core complex you can from the appearance and the function distinguish the following nuclei: the large olivary nucleus principalis and the adjacent "side Olives" - the accessory olivary nucleus and medial accessory olivary nucleus posterior.

There is also the nuclei of the superior olivary that are functional but not counted among the previous cores, since nerve fibers are switched from the auditory pathway and thus functionally unrelated to the actual function ( motor coordination ) of the other olive stones have in common. You have a function in directional hearing.