Synapses Flashcards

1
Q

Why is Chemical Conduction slower than Electrical Conduction?

A

Electrical synapse has no time gap

Chemical synapses have a delay because of the synaptic cleft

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2
Q

Differentiate Based on Ion Flow:

Electrical Synapse
Chemical Synapse

A

E: Bidrectional
C: Unidirectional

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3
Q

3 Different Types of Intercellular Communication

A

Paracrine
Endocrine
Synaptic

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4
Q

Synaptic Transmission Pathway

A
  1. Nerve is Stimulated
  2. AP travels down to terminal end causing depolarization of pre-synaptic membrane
  3. Voltage gated Ca channels in pre-synaptic membrane open
  4. Ca ions from extracellular compartment enters, increasing intracellular Ca concentration
  5. Ca ions bind to synaptic vesicles containing NT causing their release from the actin cytoskeleton (Via Synapsin)
  6. Synaptic vesicles move toward and dock at the presynaptic membrane
  7. Interaction with docking proteins creates a fusion pore through which NT pass by exocytosis
  8. NT released from presynaptic membrane, transverses the synaptic cleft, and binds to its receptors at the postsynaptic membrane
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5
Q

Function: VAMPs

A
  • Sensitive to Ca2+

- Serves as a sensor for vesicle to move towards pre-SM

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6
Q

Function: Synapsin

A

Connects vesicles to actin filament

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7
Q

Discuss the role of calcium ions in synaptic transmission

A

They are essential to release neurotransmitters

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8
Q

Define: Excitatory Postsynaptic Potential

A

Depolarization of a membrane that increases excitability of the cell

Drives membrane towards the threshold, making it more positive

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9
Q

Define: Localized Ligand-Gated Event

A

A single EPSP generally does not produce an AP, more are needed to reach firing level

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10
Q

Define: Inhibitory Postsynaptic Potential

A

Depolarization or hyperpolarization of a membrane that decreases the cells excitability

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11
Q

Major Ions Involved in:

EPSP
IPSP

A

EPSP: Na
IPSP: Cl, K

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12
Q

Peripheral Synapses are purely?

A

Excitatory

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13
Q

Central Synapses are Excitatory or Inhibitory?

A

Both

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14
Q

Is a Neuromuscular Junction a Peripheral or Central Synapse?

A

Peripheral

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15
Q

[Peripheral vs. Central Synapse]

Connections

A

Peripheral: 1 Motor Neuron -> Several Muscle Fibers

Central: Multiple Connections

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16
Q

[Peripheral vs. Central Synapse]

Ion Channels

A

Peripheral: Single

Central: Different Ion Channels

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17
Q

[Peripheral vs. Central Synapse]

Type of Input

A

Peripheral: Excitatory Only

Central: Excitatory and Inhibitory

18
Q

[Peripheral vs. Central Synapse]

Neurotransmitter

A

Peripheral: Acetylcholine Only

Central: Different Types

19
Q

Define: Temporal Summation

A

Overlap in time of firing neurons resulting in an AP

20
Q

Define: Spatial Summation

A

Overlap in location of synaptic potentials that can result in an AP

21
Q

Define: Long-Term Potentiation

A

Increased Ca causes increase in NT which strengthens the post-SM

Lasts for several hours-days

22
Q

Define: Posttetanic Potentiation

A

Repetitive stimulation of pre-synaptic membrane increases postsynaptic membrane potential

When impulse is removed, there is still a small increase in amplitude of postsynaptic potentials for some time because of opened calcium-gated channels

23
Q

2 Types of Postsynaptic Inhibition

A

Indirect

Direct

24
Q

Define: Direct Postsynaptic Inhibition

A

Inhibitory neuron releases inhibitory NTs causing increase in Cl- conductance, results in hyperpolarization

25
Q

Define: Indirect Postsynaptic Inhibition

A

Refractory Period

26
Q

Define: Pre-synaptic Inhibition

A

Inhibitor acts on the excitatory axon and decreases its capacity to deliver an excitatory impulse

Results in a hyperpolarization of the ending such that if a normal impulse arrives, it still cannot fire

27
Q

Function: Acetylcholine

A

Control of movement
Cognition
Autonomic control

28
Q

[Acetylcholine]

Inhibitory in?
Excitatory in?

A

Inhibitory: Heart
Excitatory: Neuromuscular Junction

29
Q

Function: Catecholamine

A

Feeling or Emotion
Alertness
Pain Modulation
Vasoconstriction/Dilation in Smooth Muscles of BVs

30
Q

Function: Dopamine

A

Control of Movement
Affect
Reward

31
Q

Function: Serotonin

A

Rousal (from sleep)
Mood
Modulation of Pain
Gut Regulation

32
Q

Function: Glutamate

A

General Excitation

General Sensation

33
Q

Function: Glycine

A

General Inhibition

34
Q

Function: GABA

A

General Inhibition

35
Q

Effect: Tetanus Toxin

A

Binds with docking proteins inhibiting release of NTs

May inhibit inhibitory neurons causing spastic motions

36
Q

Effect: Botulinum Toxin

A

Inhibits muscle contractions

37
Q

Botulinum types and where they bind

A

A&E: Docking protein SNAP25
B, D, F & G: Synaptobrevin
C1: Syntaxin

38
Q

Effect: Conotoxin

A

Acts on synapses

Treatment for pain and seizures in epileptic patients

39
Q

Define: Ionotropic Receptors

A

Contain ion channels that allow passage of specified ions through membrane

“Fast” Synaptic Transmission

40
Q

Define: Metabotropic Receptors

A

Coupled to G-Protein that serves as second messengers that affect ion channels

“Slow” Synaptic Transmission

41
Q

Fast synaptic transmission uses what receptors?

A

Ionotropic Receptors

42
Q

Slow synaptic transmission uses what receptors?

A

Metabotropic Receptors