Neurons:
- have a cell membrane, cytoplasm, mitochondria, and a nucleus.
- have specialized cell structure that enable them to transmit nerve impulses.
- different shapes and sizes.
- common features: dendrites, a cell body, am axon, and branching ends.
- Dendrites:
- short, branching terminals that receive nerve impulses from other neurons or sensory receptors, and relay the impulse to the cell body.
- numerous and highly branched: increases the surface area
- Cell body:
- contains the nucleus and is the site of the cell's metabolic reactions.
- processes input from the dendrites.
- Axon:
- conducts impulses away from the cell body.
- ranges from 1mm-1m.
- In order to communicate with the nearby neurons, glands or muscles, axon terminal releases chemical signals into the space between it and the receptors or dendrites.
- Myelin Sheath:
- fatty insulating layer of some neurons.
- gives the axons white appearance.
- protects neurons and speeds the rate of nerve impulse transmission.
- Schwann Cells:
glial cell, from myelin by wrapping themselves around axon.
Types of Neurons (Classified Structurally)
Types of Neurons (Classified Functionally)
Reflect Arc:
- Moves directly to and from brain or spinal cord before the brain centres involved with voluntary control have time to process the sensory information.
- Reflex arcs:
- Simple connections of neurons that result in reflexive behaviours.
- Reflexes:
- Involuntary responses to certain stimuli.
- must have input.
- very rapid.
