Classifying Neurons & Glia

classification and functions within the CNS:

- ex. primary sensory neurons, motor neurons

- Brain region specific neurons

- based on axonal length

- gene expression

- neurotransmitter

- number of neurites

- dendritic and somatic morphology

How to classify neurons?

Golgi type I

long axons, extend from one brain region to another (projection neurons)

Golgi type II

Short axons. Do not extend beyond their immediate brain region. Local circuit neurons

Glia- Astrocytes

most numerous glia in the brain, fill spaces between neurons, influence neurite growth, regulate chemical content of extracellular

Glia- Myelinating

Functional purpose to insulate and protect axons, increase action potential conduction (saltatory conduction)

Glia- Myelinating (Node of Ranvier)

Region where axonal membrane is exposed between adjacent myelinating cells

Glia- Microglia

-specialized form of glia, functions as phagocytes, resident immune cells in the brain

- involved in regulating synapse numbers

- pruning/elimination of synapses

Neurofilaments

What is the structural element made up of largest protein subunit?

microtubule > neurofilament > microfilament

Cell structural element from large to smallest