Synaptic transmission

Synapses

• Gaps between the end of the axon of one neuron and the dendrite of another neuron

• Here action potential is transmitted

What is summation?

The rapid build up (addition) of neurotransmitters in the synapse to help generate an action potential

Why is summation needed?

Some action potentials do not result in sufficient concentrations of neurotransmitter being released to help generate a new action potential

What are the 2 types of summation?

• Spatial summation

• Temporal summation

Describe spatial summation

When multiple presynaptic neurons collectively combine neurotransmitter to exceed threshold value

Describe temporal summation

When one neuron releases neurotransmitter repeatedly over a short period of time to add up enough to exceed threshold value (increased frequency)

What is a neuromuscular junction?

Synapse that occurs between the motor neuron and a muscle

Describe the response to stimulus (6 steps)

1. Stimulus

2. Receptors

3. Sensory neurone

4. Coordinator/relay neurone

5. Motor neurone

6. Effector

Give a similarity between a neuromuscular junction and cholinergic synapse

One directional movement of neurotransmitter due to receptors only being on postsynaptic membrane

Give 4 differences between a neuromuscular junction and cholinergic synapse

• Only excitatory/ Excitatory or inhibitory

• Connects motor neurons to muscles/ Connects 2 neurons

• End point of action potential/ A new action potential is generated in the next neuron

• Acetylcholine binds to receptors on muscle fibre membranes/ Acetylcholine binds to receptors on postsynaptic membrane of neuron