Neurons

What are they?:

• Bodies primary communication system

• Uses both Electrical and Chemical signals

Types of Neurons:

• Sensory Neuron: Sensory information from PNS to the CNS

• Relay Neuron: Found in the brain and spinal cord

  • allowing sensory and motor neurons to communicate

• Motor neurons:

  • Movement: Connects CNS to

  • Effectors: Muscles and organs

The basic structure of the neuron:

• The soma: Cell body which includes the nucleus

• Dendrites: Branch like structures from the body and down the axon

• Synaptic terminal: Found at the end of a neuron

• Synapses: The gap between neurons

Synaptic:

• The action potential (signal) reaches the presynaptic terminal

• Synaptic vesicals containing neuro-transmitors move to the synaptic cleft

• Neurotransmitters defuse across the synaptic cleft and bind to receptors on the post synaptic neuron

Excilation:

• Increase in positive change increasing the likelihood of neuron firing

Inhibition:

• Increase in negative charge decreasing the liklihood of the neuron firing

Summation:

• The net effect of both inhibitory and and excitatory neurotransmittors on the post synaptic neuron

• If net effect is excitatory it is more likely to fire

Action potential:

• If summation is over the threshold an action potential is initiated

• Positive ions flow into the cell passing the message down the exon to the next neuron