CMB1004/L13 Functional Neuronal Pathways

Question 1

Describe divergence.

Answer 1

Presynaptic neurone branches to affect a large number of postsynaptic neurones/collateral axons

Question 2

Describe convergence.

Answer 2

A large number of presynaptic neurones converge to affect a smaller number of postsynaptic neurones

Question 3

Describe spatial summation.

Answer 3

When multiple stimuli are applied simultaneously in different areas and have a cumulative effect on membrane potential

Question 4

Give an example of spatial summation.

Answer 4

Postsynaptic inhibition
Two EPSPs are diminished by summation with an IPSP

Question 5

What condition must be met for spatial summation to occur?

Answer 5

Graded potentials must arrive at trigger zone close enough together in time

Question 6

Describe temporal summation.

Answer 6

Summing that occurs from graded potentials overlapping in time

Question 7

Give a property of neurones demonstrated by summation of graded potentials.

Answer 7

Postsynaptic integration

Question 8

What does postsynaptic integration allow when multiple signals reach a neurone?

Answer 8

Evaluation of strength and duration of signals

Question 9

Where do neurones terminate?

Answer 9

On or close to presynaptic axon terminals

Question 10

Name 4 similarities in presynaptic mechanisms.

Answer 10

Action potential
Ca2+ channel opens
Ca2+ rise causes exocytosis
Neurotransmitter diffuses across synaptic cleft

Question 11

Name 2 differences in postsynaptic mechanisms.

Answer 11

Neurotransmitter identity differs
Receptor identity differs and work differently

Question 12

Name 3 amine neurotransmitters.

Answer 12

Adrenaline
Dopamine
Histamine

Question 13

Name 3 amino acid neurotransmitters.

Answer 13

Glutamate
GABA
Glycine

Question 14

Name 2 polypeptide neurotransmitters.

Answer 14

Cholecystkinin
Enkephalins

Question 15

Name 2 purine neurotransmitters.

Answer 15

ATP
AMP

Question 16

Name a gaseous neurotransmitter.

Answer 16

Nitric oxide

Question 17

Name the 2 mechanisms by which neurotransmitters work.

Answer 17

Ligand-gated ion channels
G-protein coupled receptors that activate second messenger systems

Question 18

Name 2 ionotropic receptors.

Answer 18

Acetylcholine
Glutamine
GABA
Glycine

Question 19

Name 2 metabotropic receptors.

Answer 19

Adrenaline
Histamine
Cholecystokinin
ATP
Acetylcholine

Question 20

What is another name for ionotropic (fast) receptors?

Answer 20

Nicotinic

Question 21

What is another name for metabotropic (slow) receptors?

Answer 21

Muscarinic

Question 22

What can cause rearrangements of circuit connections in the nervous system?

Answer 22

Variation in electrical activity

Question 23

What can cause a change in synaptic transmission at a given synapse?

Answer 23

Synaptic plasticity
Change in response to sensory input from e.g., past experience

Question 24

Give an example of synaptic plasticity.

Answer 24

Long-term potentiation

Question 25

Describe long-term potentiation.

Answer 25

Process by which repetitive stimulation at a synapse increases efficacy of transmission at that synapse

Question 26

How is long-term potentiation prevented?

Answer 26

By removing Ca2+ from extracellular medium

Question 27

Where was long-term potentiation first observed?

Answer 27

Hippocampus