Neurotransmitters & Synaptic Transmission

Question 1

Structure & Function of Sensory neuron

Answer 1

• carry nerve impulses/messages from sensory receptors, e.g. eyes, ears, tongue, skin to brain/spine
• located within sensory receptors
• cell body in middle

Question 2

Structure & Function of Motor neuron

Answer 2

• carry messages to muscles
  stimulation = release neurotransmitter that binds to muscle receptor to trigger movement response
• located in CNS
• axons connected to muscles

Question 3

Structure & Function of Relay neuron

Answer 3

• allow sensory and motor neurons to communicate with each other
• located in brain/spine, between motor/sensory neurons
• no myelin sheath

Question 4

What are neurotransmitters

Answer 4

chemical messengers, found in synaptic vesicles at end of neuron

Question 4

Role of Inhibitory Neurotransmitters

Answer 4

Inhibitatory (e.g. serotonin, GABA)
- reduce potential difference across the postsynaptic membrane by increasing negative charge (close Na+ channels) = reduce likelihood of generating action potential/less likely to fire

Question 5

What is summation

Answer 5

sum of excitatory and inhibitatory effects (nerve cell can recieve both simultaneously)
- net effect (the one that is greater) = determine action of neuron

Question 6

Process of synaptic transmission

Answer 6

1. info passed down axon as action potential (electrical impulse)
2. action potential reaches end of axon = needs to be transferred to another neuron/tissue.
3. action potential reaches synaptic vesicles, they release contents of neurotransmitters = carry signal across the pre/post synaptic gap
4. neurotransmitters bind to receptor sites on post-synaptic cell = become activated
5. activated receptors = produce inhibitory/excitatory effects on the post-synaptic cell

Question 7

Role of Excitatory Neurotransmitter

Answer 7

Excitatory (e.g. dopamine)
- increase potential difference across
postsynaptic membrane by increasing positive charge (open more Na+ channels)
increase likelihood of generating action potential/more likely to fire