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[OS 202] Lecture Exam A > Synapses > Flashcards

Flashcards in Synapses Deck (42):
1

Why is Chemical Conduction slower than Electrical Conduction?

Electrical synapse has no time gap

Chemical synapses have a delay because of the synaptic cleft

2

Differentiate Based on Ion Flow:

Electrical Synapse
Chemical Synapse

E: Bidrectional
C: Unidirectional

3

3 Different Types of Intercellular Communication

Paracrine
Endocrine
Synaptic

4

Synaptic Transmission Pathway

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

5

Function: VAMPs

- Sensitive to Ca2+
- Serves as a sensor for vesicle to move towards pre-SM

6

Function: Synapsin

Connects vesicles to actin filament

7

Discuss the role of calcium ions in synaptic transmission

They are essential to release neurotransmitters

8

Define: Excitatory Postsynaptic Potential

Depolarization of a membrane that increases excitability of the cell

Drives membrane towards the threshold, making it more positive

9

Define: Localized Ligand-Gated Event

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

10

Define: Inhibitory Postsynaptic Potential

Depolarization or hyperpolarization of a membrane that decreases the cells excitability

11

Major Ions Involved in:

EPSP
IPSP

EPSP: Na
IPSP: Cl, K

12

Peripheral Synapses are purely?

Excitatory

13

Central Synapses are Excitatory or Inhibitory?

Both

14

Is a Neuromuscular Junction a Peripheral or Central Synapse?

Peripheral

15

[Peripheral vs. Central Synapse]

# Connections

Peripheral: 1 Motor Neuron -> Several Muscle Fibers

Central: Multiple Connections

16

[Peripheral vs. Central Synapse]

# Ion Channels

Peripheral: Single

Central: Different Ion Channels

17

[Peripheral vs. Central Synapse]

Type of Input

Peripheral: Excitatory Only

Central: Excitatory and Inhibitory

18

[Peripheral vs. Central Synapse]

Neurotransmitter

Peripheral: Acetylcholine Only

Central: Different Types

19

Define: Temporal Summation

Overlap in time of firing neurons resulting in an AP

20

Define: Spatial Summation

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

21

Define: Long-Term Potentiation

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

Lasts for several hours-days

22

Define: Posttetanic Potentiation

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

2 Types of Postsynaptic Inhibition

Indirect
Direct

24

Define: Direct Postsynaptic Inhibition

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

25

Define: Indirect Postsynaptic Inhibition

Refractory Period

26

Define: Pre-synaptic Inhibition

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

Function: Acetylcholine

Control of movement
Cognition
Autonomic control

28

[Acetylcholine]

Inhibitory in?
Excitatory in?

Inhibitory: Heart
Excitatory: Neuromuscular Junction

29

Function: Catecholamine

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

30

Function: Dopamine

Control of Movement
Affect
Reward

31

Function: Serotonin

Rousal (from sleep)
Mood
Modulation of Pain
Gut Regulation

32

Function: Glutamate

General Excitation
General Sensation

33

Function: Glycine

General Inhibition

34

Function: GABA

General Inhibition

35

Effect: Tetanus Toxin

Binds with docking proteins inhibiting release of NTs
May inhibit inhibitory neurons causing spastic motions

36

Effect: Botulinum Toxin

Inhibits muscle contractions

37

Botulinum types and where they bind

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

38

Effect: Conotoxin

Acts on synapses
Treatment for pain and seizures in epileptic patients

39

Define: Ionotropic Receptors

Contain ion channels that allow passage of specified ions through membrane

"Fast" Synaptic Transmission

40

Define: Metabotropic Receptors

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

"Slow" Synaptic Transmission

41

Fast synaptic transmission uses what receptors?

Ionotropic Receptors

42

Slow synaptic transmission uses what receptors?

Metabotropic Receptors