Neuronal signalling in the context of CNS disorders

Question 1

what does the axon do?

Answer 1

Transmits information between cell body and axon terminals.

Question 2

what does the cell body do?

Answer 2

Receives inputs (e.g. from sense organs, other neurones) and encodes these inputs

Question 3

what does the axon terminal do?

Answer 3

Serves as the output sends signals to other neurones, muscles and other effectors (exocrine organs etc).

Question 4

what is electrical signalling along a neuron?

Answer 4

the action potential transmitted along the neuron

Question 5

what is chemical signalling across the neuron?

Answer 5

the transmission of neurotransmitters

Question 6

what makes up the resting membrane potential?

Answer 6

• Na+ (and Cl-) are concentrated outside
• K+ (and A-) are concentrated inside
• The ionic charge between inside and outside is unequal
• Inside is more negative than outside

Question 7

what allows the neurons to alter their membrane potential and propagate action potentials (AP) along an axon?

Answer 7

voltage-gated ion channels

Question 8

what does the myelin sheath do?

Answer 8

1. Insulates the axon to prevent AP from leaking

2. Allows faster transmission of signal via nodes of Ranvier

Question 9

where are neurotransmitters stored when the presynaptic neuron is at rest?

Answer 9

in the synaptic vesicles

Question 10

what are the three criteria’s that must be met to be identified as a neurotransmitter?

Answer 10

1. Must be LOCALISED i.e. lives in that neuron
2. Must be RELEASED i.e. able to release it from the terminal upon activation
3. Must be IDENTIFIED i.e. has same identity as other neurotransmitters from that same neuron (so has same effect as them)