Neurons

• neurons structure

  A) conduction

  B) ranvier

  C) myelin

  D) sensory

  E) relay

  F) motor

  
• the myelin sheath is a fatty layer that covers the axon in order to protect it and speed up electrical transmission of the impulse BUT if the myelin sheath was continuous, it would actually have the effect of slowing down the electrical impulse

  Hence why the myelin sheath is split up by gaps called nodes of ranvier which speed up transmission by forcing it to jump along the gaps
• the change in charge of a neuron causes an action potential which creates an electrical impulse that travels down the axon
• acetylcholine is found at each point where a motor neuron meets a muscle and when released, will cause muscles to contract
• excitation is when a neurotransmitter increases the positive charge of the post synaptic neuron which increases the likelihood that the neuron will fire and pass on the electrical impulse. inhibition is the opposite of this.
• summation is the net charge on the postsynaptic neuron which will determine if the neuron will fire and pass on an electrical impulse