- neurons are fully differentiated cells. Lower animals still have neurogenesis.
Humans have a little bit.
- Glia (glue) – Neurons fully depend on Glia. Also important in signalling (not only
because they provide myelin), control ionic environment. Glial cells can mostly
- Pseudounipolar neurons are rare and are sensory
- Bipolar (in human retina), rare as well.
- Motor neurons
- 99% of neurons are ‘interneurons’ (more common is interneurons and projection
neurons), inside our brain. Every neuron has only one axon but can have many dendrites.
Very different shapes
- Motor neuron body sits in spinal cord (20 um in diameter).
- Picture is not to scale, axon is VERY long
- Dendrites are tapered, axons are not.
- Nissl bodies (rER). Processes do not stain well. Other nuclei are probably from Glial