The nervous system

Nervous System Function

Communication and control

Cells of the nervous system

**Nerve cells** (neurones)- function is communication and control

**Glial cells**- function is to support neuron’s and its environment

Nerve Cell Structure

**Dendrites**- collect chemical messengers

**Terminal**- storage structures

Myelinated axon

**Myelin**- fatty substance, lipid material which insulated axon

**Schwann cells**- type of glial cell which grabs hold of axon & wraps round it (ONLY FOUND IN PNS)

**Oligodendroglial cells**- The glial cell involved in myelination in CNS

**Nodes of ranvier**- the gaps

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Myelination

**PNS**- Schwann cells

**CNS**- Oligodendroglial cell

Glial cells of CNS

**Astrocyte**- form part of the blood brain barrier

**Oligodendroglial cell-** myelination

**Endymal cells**- line of cerebral ventricles (line the fluid filled spaces)

**Microglial cells**- phagocytic cells (defensive cells)

-attack and destroy invading cells

Nerve

A bundle of axons running together outside the CNS

Structure of a Nerve

**Epinerium**- protective wrapping around nerves

**Fascicle**- smaller bundle of axons within a nerve

**Perineurium**- protective wrapping around endoneurium

**Endoneurium**- wrapping around axon

Tract

Bundle of axons running together inside the CNS

Ulnar Nerve

Funny bone nerve

\-if damaged can loose motor and sensory neurones (lose of sensation in that region)

Nerve Damage

Distal (beyond the damage)

\-All axons distal begin to break

\-Schwann cells don’t break

\-Macrophage cells clear debris

\-Schwann cells form a line

\-Axon begins to regenerate

\-Schwann cells guide the new axon to its destination

\-Axon growth is 1mm per day