Synaptic Transmission

Question 1

Identify the main features of electrical synapses

Answer 1

• Simple structure and function
• Faster
• Passive signal transmission (no energy)
• Bidirectional
• They are the minority of synapses

Question 2

Describe an axodendritic chemical synapse

Answer 2

Presynaptic axon synapses with post synaptic dendrite

Question 3

Describe an axosomatic chemical synapse

Answer 3

Presynaptic axon synapses with post synaptic soma

Question 4

Describe an axoaxonic chemical synapse

Answer 4

Presynaptic axon synapses with post synaptic axon before both synapsing with soma of another postsynaptic cell

Question 5

Where does a neuromuscular junction occur?

Answer 5

Between a motor neuron and muscle cell

Question 6

What occurs in response to a direct excitatory or inhibitory neurotransmission?

Answer 6

The membrane of the next cell becomes slightly depolarised or hyperpolarised

Question 7

What occurs in response to a neuromodulation synaptic transmission?

Answer 7

Alters the presynaptic cell’s ability to release more transmitters or the postsynaptic cells ability to respond

Question 8

What are the 4 criteria that define a neurotransmitter?

Answer 8

1. synthesised in the neuron
2. present in presynaptic terminal and released in amounts sufficient to exert a defined effect on the postsynpatic neuron or effector organ
3. when administered exogenously it mimics the action of the endogenously released transmitter
4. a specific mechanism exists for removing it from the synaptic cleft

Question 9

What occurs upon the depolarisation of the presynaptic terminal?

Answer 9

Depolarisation causes opening of voltage-gated calcium channels

Question 10

How is the neurotransmitter removed from the synaptic cleft?

Answer 10

By glial cell uptake or enzymatic degradation