Neurons, synaptic transmission and neurotransmitters

Question 1

What is a neuron?

1

Answer 1

• Nerve cells that process/transmit messages through electrical/chemical signals

Question 2

What is the function of a neurotransmitter?

1

Answer 2

• Relay signals from 1 neuron to another across a synapse

- Excitatory or Inhibitory

Question 3

What is the function of a cell body (soma)?

1

Answer 3

• Inc. nucleus containing genetic material of the cell

Question 4

What is the function of a dendrite?

1

Answer 4

• Branch structure, carry impulses from neighbouring neurons toward cell body

Question 5

What is the function of an axon?

1

Answer 5

• Tube-like structure, carries impulses away from cell body down neuron

Question 6

What is the function of myelin sheath?

1

Answer 6

• Fatty layer that protects the axon and speeds up electrical transmission

Question 7

What is the function of node of Ranvier?

1

Answer 7

• Gap in myelin sheath that allow increase in speed by forcing impulses to jump across the gaps along axon

Question 8

What is the function of terminal buttons?

1

Answer 8

• End of axon, involved in comm across the synapse

Question 9

What is the function of sensory neurons?

2

Answer 9

• Carry msgs from sensory receptors along nerves in the PNS to the CNS
• Long dendrites, short axons

Question 10

What is the function of motor neurons?

2

Answer 10

• Carry msgs from CNS, along nerves in PNS, to effectors e.g. muscles/glands
• Short dendrites, long axons

Question 11

What is the function of relay neurons?

2

Answer 11

• Connect sensory/motor neurons together, only in CNS

- Short dendrites, short axons

Question 12

What is the process of synaptic transmission?

4

Answer 12

• AP generated once depolarisation reaches certain threshold
• AP travels down axon, when it reaches end of neuron (terminal button) triggers release of NT from synaptic vesicles
• NT then diffuse across synapse to next neuron, binding to matching receptor sites on post synaptic neuron
• NT remaining in synapse = re-absorbed through re-uptake channels

Question 13

What is an excitatory NT?

1

Answer 13

• Dopamine NT causes excitation by ^positive charge, making it more likely to fire

Question 14

What is an inhibitory NT?

1

Answer 14

• Serotonin NT causes inhibition, making neuron more negatively charged, less likely to fire

Question 15

What is an example of summation?

1

Answer 15

• If net effect on PS neuron = inhibitory (less likely to fire