Synapses

Question 1

What are the 2 types of synapse?

Answer 1

Electrical synapses

Chemical synapses

Question 2

How do electrical synapses work?

Answer 2

Use gap junctions to allow direct ion flow between neurons

Question 3

What is the directionality of electrical synapses?

Answer 3

Bidirectional

Question 4

Where are electrical synapses found?

Answer 4

Synchronized networks

Question 5

How do chemical synapses work?

Answer 5

Use neurotransmitters to transmit signals across a synaptic cleft

Question 6

What is the directionality of chemical synapses?

Answer 6

Unidirectional

Question 7

Where are peptide neurotransmitters synthesized?

Answer 7

Neuron cell body

Question 8

Where are amine and small-molecule neurotransmitters synthesized?

Answer 8

Pre-synaptic terminal

Question 9

Neurotransmitters packaged into vesicles in the pre-synaptic neuron are stored near which areas?

Answer 9

Active zones

Question 10

Describe the process of how neurotransmitters are released into the synaptic cleft via exocytosis.

Answer 10

An AP travels down the axon to the pre-synaptic terminal, where is depolarizes the membrane, opening voltage-gated Ca2+ channels.

Ca2+ influx triggers the fusion of synaptic vesicles with the pre-synaptic membrane. The vesicles release neurotransmitters into the synaptic cleft via exocytosis

Question 11

What are the 3 ways a neurotransmitter can be inactivated?

Answer 11

Reuptake

Degradation by enzymes

Diffusion away from synapse

Question 12

What are the 3 chemical classes of neurotransmitters?

Answer 12

Amino acids
Amines
Peptides

Question 13

What are the 3 amino acid neurotransmitters?

Answer 13

Gamma-aminobutyric acid (GABA)
Glutamate
Glycine

Question 14

What are the 5 amine neurotransmitters?

Answer 14

Acetylcholine
Norepinephrine
Histamine
Dopamine
Serotonin

Question 15

What is the major excitatory neurotransmitter?

Answer 15

Glutamate

Question 16

What is the major inhibitory neurotransmitter?

Answer 16

GABA

Question 17

Since peptide neurotransmitters are synthesized in the cell body, by what mechanism do they reach the pre-synaptic terminal?

Answer 17

Fast axonal transport via microtubules

Question 18

Neurotransmitters are packaged into vesicles in the pre-synaptic terminals via what?

Answer 18

Vesicular transporters (proton-coupled antiporters)

Question 19

What are the 2 types of v-snares?

Answer 19

Synaptotagmin

Synaptobrevin

Question 20

What are the 2 types of t-snares?

Answer 20

SNAP-25

Syntaxin

Question 21

Which specific SNARE does calcium bind to to trigger vesicle fusion with the pre-synaptic membrane?

Answer 21

Synaptotagmin

Question 22

What are the 2 classes of neurotransmitter receptor?

Answer 22

Ionotropic (ligand-gated ion channels)

Metabotropic (G-protein coupled receptors)

Question 23

What are the 2 potential membrane changes at the ionotropic receptors – describe polarization changes, type of cell influx, and type of neurotransmitter involved.

Answer 23

Depolarization (EPSP) – cation influx e.g. Na+ - excitatory neurotransmitters e.g. Glutamate

Hyperpolarization (IPSP) – anion influx e.g. Cl- - inhibitory neurotransmitters e.g. GABA

Question 24

Define synaptic integration.

Answer 24

The process by which a neuron combines multiple synaptic inputs (both excitatory and inhibitory) to determine whether it will generate an action potential

Question 25

What are the 3 key mechanisms of synaptic integration?

Answer 25

Spatial summation Temporal summation Shunting inhibition

Question 26

Describe what is meant by spatial summation in relation to synaptic integration.

Answer 26

Multiple synapses are activated simultaneously

Question 27

Describe what is meant by temporal summation in relation to synaptic integration.

Answer 27

A single synapse is activated repeatedly in quick succession

Question 28

Describe what is meant by shunting inhibition in relation to synaptic integration.

Answer 28

When an IPSP is located near the soma or axon hillock, reducing the magnitude of EPSPs and reducing the likelihood that EPSPs would initiate an action potential

Question 29

Synaptic plasticity / long-term synaptic changes are fundamental to which neural process?

Answer 29

Learning and memory formation in the hippocampus

Question 30

What are the 2 forms of long-term synaptic change?

Answer 30

Long-term potentiation (LTP) and long-term depression (LTD)

Question 31

Which 2 receptors are involved in long-term synaptic changes?

Answer 31

AMPA + NMDA glutamate receptors

Question 32

Which receptor is crucial for long-term synaptic changes?

Answer 32

NMDA receptor

Question 33

How is neuromodulator release different from neurotransmitter release?

Answer 33

Neuromodulators are released into the ECF

Question 34

What kind of receptors do neuromodulators act on?

Answer 34

G-protein coupled receptors

Question 35

When acting as a neuromodulator, what effect does NE have?

Answer 35

Increases the responsiveness of the post-synaptic neuron

Question 36

Which enzyme is involved in long-term synaptic change?

Answer 36

Calmodulin kinase