Neurone
Structure
Name |
Structure |
Function |
Cell body |
· Contains nucleus and large amounts of Rough Endoplasmic Reticulum |
· Associated with production of proteins + neurotransmitters |
Dendrons |
· Small extensions of the cell body · Subdivide into smaller branched fibres (dendrites) |
· Carry nerve impulses towards the cell body |
Axon |
· Single long fibre |
· Carries nerve impulses away from cell body |
Schwann Cells |
· Surrounds axon · Wraps around axon many times to form layers of membrane |
· Protects axon and provides electrical insulation · Carries out phagocytosis · Used in nerve regeneration |
Myelin Sheath |
· Forms a covering to the axon · Made up of the membranes of the Schwann cells · Rich in lipids (myelin) · Myelinated neurons are those that contain a myelin sheath |
· Transmit nerve impulses faster (relative to unmyelinated) |
Node of Ranvier |
· Gaps between adjacent Schwann cells (where there is no myelin sheath) · Gaps are 2-3μm long and occur every 1-3mm (humans) |
Types of Neuron
- Sensory Neurone:
- Transmits nerve impulses from a receptor to an intermediate/motor neuron
- Have one dendron which carries the impulse towards the cell body
- One axon that carries it away from the cell body
- Motor Neurone:
- Transmit nerve impulses from an intermediate/sensory neuron to an effector
- Have a long axon and many short dendrites
- Intermediate Neurone:
- Transmits impulses between neurones
- Numerous short processes