Macroscopic anatomy
The CNS is protected in the area of the head by the skull bones and on the back by the vertebral bodies, which form a spinal canal inside. It continues without a sharp border into the so-called “peripheral nervous system“, which emerges with its more or less long nerve fibers from the bony sheaths of the CNS. Functionally, both systems are inseparable, the division is made for reasons of clarity.
The brain and spinal cord can be divided into numerous subunits: the brain contains this:
- Cerebrum (Telencephalon)
- The Interbrain (Diencephalon)
- And at the brain stem the midbrain (mesencephalon)
- The bridge (Pons)
- As well as the direct transition from the spinal cord to the brain, the elongated medulla oblongata.
- Behind the bridge, the cerebellum sits on the brain stem.
- Finally, medulla oblongata, pons and cerebellum are also called rhombic brain (rhombencephalon).
- Cerebrum
- Cerebellum
- Spinal cord
- Pituitary gland (hypophysis)
In the brain, the grey matter, i.e. among other things the cell bodies (perikaryes) of the nerve cells, is located both in the cortex and in the subcortical core areas. The subcortical nuclei form a medullary layer, which is embedded in white matter. The spinal cord extends from the back of the head to the 1st or 2nd lumbar vertebrae and undergoes various forms during passage in the spinal canal.
In cross-section it reveals its inner structure: gray matter in the middle, which resembles the shape of a butterfly. It is surrounded at the front, back and sides by several bundles of white substance, which are called the anterior (funiculus anterior), lateral (funiculus lateralis) and posterior (funiculus posterior) strands depending on their position.It is characteristic of the CNS (central nervous system) that each section has cavities (inner and outer cerebrospinal fluid spaces at the brain, only one channel in the spinal cord), which are filled with a water clear colorless fluid (cerebrospinal fluid, “spinal fluid“): The cerebrospinal fluid is a well-controlled filtrate of the cells of the choroid plexus (singular plexus choroideus) with multiple functions: Upholstery, by considerably reducing the effective weight of the brain and absorbing shocks like a pillow. Communication both between nerve cells and between nerve cells in the sense of informing the nerve cells about the composition of the blood and controlling the environment (extracellular fluid) of nerve cells and glial cells are also among the tasks of the CSF (cerebrospinal fluid).
