Neurons and synaptic transmission

Question 1

Types of neurons

Answer 1

1) Sensory neuron - carry messages from PNS to CNS - have long dendrites and short axons
2) Relay neuron - connect sensory neurons to motor neurons - short dendrites and short axons
3) Motor neuron - connect CNS to effectors - short dendrites and long axons

Question 2

Synaptic transmission

Answer 2

• When electrical impulse reaches presynaptic neuron it triggers the release of neurotransmitters from synaptic vesicles
• Neurotransmitter diffuses across a synapse to the postsynaptic neuron where it is taken up by a receptor site

Question 3

Excitation and inhibition

Answer 3

Excitation = when a neurotransmitter - e.g adrenaline - increases the positive charge of a postsynaptic neuron - increases chance that electrical impulse will be passed on
Inhibition = when a neurotransmitter - e.g serotonin - increases the negative charge of a postsynaptic neuron - decreases chance that electrical impulse will be passed on