Synaptic Transmission Flashcards

1
Q

Do chemical or electrical synapse provide a faster transmission of a signal?

A
  • electrical
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2
Q

Do chemical or electrical synapse have more biological flexibility?

A
  • chemical
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3
Q

What is the name given to where the pre and post synapse meet in an electrical synapse?

  1. gap junctions made from connexin36
  2. gap junctions made from tight junction
  3. synaptic cleft made from connexin36
  4. synaptic cleft made from tight junction
A
  1. gap junctions made from connexin36
    - essentially holes for ions to flow through
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4
Q

Electrical synapses are connected by gap junctions between the pre and post synapse. They are gap junctions that connect the pre and post synapse at electrical synapse composed of connexin 36. How many subunits do these gap junctions have?

  1. 1
  2. 3
  3. 6
  4. 9
A
  1. 6
    - referred to as a connexon
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5
Q

When an action potential travels down the pre-synpatic terminal and transfers it to the post synapse, what is this action potential then called?

  1. pre-synaptic termination
  2. post-synaptic termination
  3. post-synaptic potential
  4. excitatory post synaptic potential
A
  1. post-synaptic potential (PSP)
  • can also be referred to as a post-synaptic potential (PSP)
  • causes change in voltage in post-synaptic cell and an action potential occurs
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6
Q

If a cell receives a postsynaptic potential (PSP) in the post synaptic cell, will this be sufficient to generate an action potential in the post synaptic cell if it only generates 1mV?

A
  • no
  • requires synaptic integration from lots of graded potentials
  • an action potential follows
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7
Q

In a chemical synapse, what is the gap between the pre and post synapse called?

A
  • synaptic cleft
  • aprox 30nm wide
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8
Q

In a chemical synapse, what is an active zone?

  1. site where neurotransmitters bind
  2. site of neurotransmitter release
  3. site where neurotransmitters are made
  4. site where neurotransmitters are recycled
A
  1. site of neurotransmitter release
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9
Q

There are 3 locations on a neuron where chemical synapses can take place, including the soma, dendrites or axon. Label the 3 sites using the labels below:

  • axondendritic synapse (axon to dendritic)
  • axonsomatic synapse (axon to soma)
  • axoaxonic synapse (axon to axon)
A

a = axondendritic synapse (axon to dendritic)

b = axonsomatic synapse (axon to soma)

c = axoaxonic synapse (axon to axon)

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10
Q

Are there more chemical or electrical synapse in the body?

A
  • chemical
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11
Q

Where are small molecule neurotransmitters synthesised?

  1. pre-synaptic terminal
  2. axon hillock
  3. cell body
  4. axon
A
  1. pre-synaptic terminal
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12
Q

Where are neuropeptides neurotransmitters synthesised?

  1. pre-synaptic terminal
  2. axon hillock
  3. cell body
  4. axon
A
  1. cell body
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13
Q

Once neurotransmitters have been synthesised in the cell body of the neuron, where are they transported to and found in their highest concentrations?

  1. pre-synapse
  2. axon hillock
  3. cell body
  4. axon
A
  1. pre-synapse
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14
Q

Once neurotransmitters are released at the pre synapse, do they randomly bind to any receptor?

A
  • no
  • selectively bind to specific targets
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15
Q

To be characterised as a neurotransmitter, if a neurotransmitter is administered, what should it do to its target receptors?

A
  • should mimic the endogenously released ligand
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16
Q

To be characterised as a neurotransmitter, if a neurotransmitter is released into the synaptic cleft, what must happen to the neurotransmitter once the action potential has finished?

A
  • it will be removed/recycled from the synaptic cleft
17
Q

Large neuropeptide neurotransmitters and small peptide neurotransmitters are synthesised in the cell body and pre-synaptic terminal, respectively, before being transported to the pre-synapse where they can be found in the highest concentrations. What does the neuronal cell use to transport the vesicles containing the neurotransmitters along the microtubules to the pre synapse?

  1. kinesin Antegrade (away from the cell body)
  2. dynenin Retrograde (to the the cell body)
  3. kinestain Retrograde (away from the cell body)
  4. dynenin Retrograde (away from the cell body)
A
  1. kinesin Antegrade (away from the cell body)
18
Q

Neurotransmitters that are produced in the cell body and then transported to the pre synapse by kinesin along the microtubules, which is referred to as Antegrade (AWAY from cell body). They can also be recycled and may need to travel back to the cell body. What does the neuronal cell use to transport the vesicles containing the neurotransmitters along the microtubules back to the cell body?

  1. kinesin Antegrade (away from the cell body)
  2. dynenin Retrograde (to the the cell body)
  3. kinestain Retrograde (away from the cell body)
  4. dynenin Retrograde (away from the cell body)
A
  1. dynenin Retrograde (to the the cell body)
19
Q

Once an action potential is received at the pre synapse, what channels open to allow vesicles containing neurotransmitters to fuse with the pre synapse membrane causing exocytosis of the neurotransmitter into the synaptic cleft?

  1. Na+ channels
  2. K+ channels
  3. Ca2+ channels
  4. Cl- channels
A
  1. Ca2+ channels
20
Q

The active zone is the site where neurotransmitters are released at the pre synapse. Once the action potential is received, a specific channel opens allowing cations to flow in. What is this cation?

  1. Na+
  2. K+
  3. Ca2+
  4. Mg+
A
  1. Ca2+
21
Q

The active zone is the site where neurotransmitters are released at the pre-synapse. Ca2+ is released and causes a conformation change in 2 proteins that are important for vesicles to fuse with the pre-synaptic membrane and release their neurotransmitters into the synaptic cleft. What are these 2 proteins called?

  1. snaps and snappers
  2. snappers and snares
  3. snares and cyndricals
  4. snares and snaps
A
  1. snares and snaps
22
Q

Once a neurotransmitter has been released into the synaptic cleft, it will need to be removed once the action potential has finished. Which glial cell is able to take up the neurotransmitters and recycle them?

  1. astrocytes
  2. oligodendrocytes
  3. microglia
  4. gliomas
A
  1. astrocytes
    - uptake, enzyme degradation and recycled back into pre synapse
23
Q

Once a neurotransmitter has been released into the synaptic cleft, it will need to be removed once the action potential has finished. If it is not recycled by astrocytes or at the pre-synapse, what can happen to it?

A
  • degraded in the synaptic cleft to make it inactive
  • example, is acetylcholinesterase in the image
24
Q

Once a neurotransmitter has been released into the synaptic cleft, it will need to be removed once the action potential has finished. What are the 2 approaches that can be used to recycle the neurotransmitter by the pre synapse?

A

1 - endocytosis and repackaged into vesicles

2 - endocytosis and degraded and made inactive

25
Q

What is a motor end plate?

A
  • site where the pre-synapse meets a muscle at the neuromuscular junction
26
Q

At the axon terminal of a neuromuscular junction, do Schwann cells completely encompass the axon terminals?

A
  • no
  • protects the nerve from the fluid surrounding the neuromuscular junction
27
Q

At the neuromuscular junctions the synaptic cleft is not flat, which is the case in nerve pre to post synapse. Instead it has grooves that resemble the crypts in the GI tract, called subjunctional folds/subneural clefts. What is the purpose of this?

A
  • increase surface area for neurotransmitter action
  • increases the chance of an action potential
28
Q

In the image below, what is the dense bar also referred to as?

  1. active zone
  2. synaptic cleft
  3. synaptic membrane
  4. snaps zone
A
  1. active zone
    * where neurotransmitters are released from pre-synapse
29
Q

From one action potential, roughly how many vesicles are likely to bind with the pre synapse and release neurotransmitters at a neuromuscular junction?

A
  • > 125
30
Q

Acetylcholine (ACh) is able to bind with ionotropic receptors on the post-synapse. These are Na+ channels that are present at the neuromuscular junction. The receptors are composed of 2 alpha, 1 gamma, 1 beta and delta subunit. What 2 subunits of the ACh receptor does ACh bind with?

  1. one alpha and one beta
  2. both alpha
  3. alpha and gamma
  4. gamma and beta
A
  1. both alpha
31
Q

Acetylcholine (ACh) binds with sodium channels that are present at the neuromuscular junction. ACh binds with 2 alpha subunits on the Na+ channels, but is it only Na+ that can pass through these channels?

A
  • no
  • K+ and Ca2+ can also pass, but mainly Na+
32
Q

At the neuromuscular junction, once an action potential has been received, ACh has been released and binds at the post synaptic cleft causing depolarisartion. There is a graded potential which causes the Na+ channels to open increasing the action potential, which leads to a muscle contraction. What is this called?

  1. post-synaptic action potential
  2. post-synaptic excitatory potential
  3. end plate potential
  4. active zone potential
A
  1. end plate potential