The nervous system of the model is the brain: 98 named parts in 4 groups, with 37 nerves of the eye socket as a fifth group. The white matter of each cerebral hemisphere measures 16.3 cm from front to back. The model has no spinal cord and no nerves of the trunk or limbs.
The nervous system of the model in 5 groups
| Group | Parts | What it holds |
|---|---|---|
| Cerebral cortex | 36 | The folds of the surface, such as the superior frontal gyrus and the cingulate gyrus |
| Deep brain structures | 37 | The white matter and the parts that lie under the cortex |
| Brainstem and cerebellum | 16 | The midbrain, the pons, the medulla oblongata and the cerebellum |
| Ventricles | 9 | The fluid-filled spaces inside the brain |
| Nerves of the eye socket | 37 | The nerves that run to the eyes and their muscles |
The skull is drawn as glass, so the brain shows in place. Each group has its own switch beside the model. Switch off the cerebral cortex to reach the deep structures and the ventricles.
The 4 divisions of the brain
The brain has 4 divisions, according to the National Cancer Institute: the cerebrum, the diencephalon, the brain stem and the cerebellum.
| Division | What the source says | In the model |
|---|---|---|
| Cerebrum | The largest part, in 2 hemispheres joined by the corpus callosum | The cerebral cortex and the white matter of each hemisphere |
| Diencephalon | The thalamus, about 80 percent of it, relays every sense except smell | Among the deep brain structures |
| Brain stem | The midbrain, the pons and the medulla oblongata | Midbrain, pons and medulla oblongata, each a part |
| Cerebellum | The second largest part, below the occipital lobes | One part, behind the brainstem |
The medulla oblongata continues into the spinal cord, and all the fibers between the brain and the cord pass through it. Tap the pons in the model, press Pull it out, and the brainstem can be turned around on its own.
The central and the peripheral nervous system
The nervous system has 2 divisions. The central nervous system is the brain and the spinal cord. The peripheral nervous system is the nerves and the ganglia outside them.
The spinal cord runs from the base of the skull to the level of the first lumbar vertebra. It has 31 segments, and each segment gives rise to a pair of spinal nerves. There are 12 pairs of cranial nerves, which leave the brain itself.
Nerve tissue has 2 kinds of cell. Neurons conduct impulses, and neuroglia support them. The National Cancer Institute notes that neuroglia are far more numerous than neurons.
What the model leaves out
The model has no spinal cord, no spinal nerves and no nerves of the trunk, arms or legs. Of the 12 pairs of cranial nerves it shows the ones in the eye socket. The meninges are not drawn, apart from the tentorium cerebelli.
The brain is that of one adult man. The eyes that the nerves of the eye socket serve are in the 3D eye and ear view. The pituitary gland and the pineal body, which sit against the brain, are in the 3D endocrine system, and the bones around the brain are in the 3D skeleton.