Synapses

Question 1

Why is Chemical Conduction slower than Electrical Conduction?

Answer 1

Electrical synapse has no time gap

Chemical synapses have a delay because of the synaptic cleft

Question 2

Differentiate Based on Ion Flow:

Electrical Synapse
Chemical Synapse

Answer 2

E: Bidrectional
C: Unidirectional

Question 3

3 Different Types of Intercellular Communication

Answer 3

Paracrine
Endocrine
Synaptic

Question 4

Synaptic Transmission Pathway

Answer 4

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

Question 5

Function: VAMPs

Answer 5

• Sensitive to Ca2+

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

Question 6

Function: Synapsin

Answer 6

Connects vesicles to actin filament

Question 7

Discuss the role of calcium ions in synaptic transmission

Answer 7

They are essential to release neurotransmitters

Question 8

Define: Excitatory Postsynaptic Potential

Answer 8

Depolarization of a membrane that increases excitability of the cell

Drives membrane towards the threshold, making it more positive

Question 9

Define: Localized Ligand-Gated Event

Answer 9

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

Question 10

Define: Inhibitory Postsynaptic Potential

Answer 10

Depolarization or hyperpolarization of a membrane that decreases the cells excitability

Question 11

Major Ions Involved in:

EPSP
IPSP

Answer 11

EPSP: Na
IPSP: Cl, K

Question 12

Peripheral Synapses are purely?

Answer 12

Excitatory

Question 13

Central Synapses are Excitatory or Inhibitory?

Answer 13

Both

Question 14

Is a Neuromuscular Junction a Peripheral or Central Synapse?

Answer 14

Peripheral

Question 15

[Peripheral vs. Central Synapse]

Connections

Answer 15

Peripheral: 1 Motor Neuron -> Several Muscle Fibers

Central: Multiple Connections

Question 16

[Peripheral vs. Central Synapse]

Ion Channels

Answer 16

Peripheral: Single

Central: Different Ion Channels

Question 17

[Peripheral vs. Central Synapse]

Type of Input

Answer 17

Peripheral: Excitatory Only

Central: Excitatory and Inhibitory

Question 18

[Peripheral vs. Central Synapse]

Neurotransmitter

Answer 18

Peripheral: Acetylcholine Only

Central: Different Types

Question 19

Define: Temporal Summation

Answer 19

Overlap in time of firing neurons resulting in an AP

Question 20

Define: Spatial Summation

Answer 20

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

Question 21

Define: Long-Term Potentiation

Answer 21

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

Lasts for several hours-days

Question 22

Define: Posttetanic Potentiation

Answer 22

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

Question 23

2 Types of Postsynaptic Inhibition

Answer 23

Indirect

Direct

Question 24

Define: Direct Postsynaptic Inhibition

Answer 24

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

Question 25

Define: Indirect Postsynaptic Inhibition

Answer 25

Refractory Period

Question 26

Define: Pre-synaptic Inhibition

Answer 26

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

Question 27

Function: Acetylcholine

Answer 27

Control of movement Cognition Autonomic control

Question 28

[Acetylcholine] Inhibitory in? Excitatory in?

Answer 28

Inhibitory: Heart Excitatory: Neuromuscular Junction

Question 29

Function: Catecholamine

Answer 29

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

Question 30

Function: Dopamine

Answer 30

Control of Movement Affect Reward

Question 31

Function: Serotonin

Answer 31

Rousal (from sleep) Mood Modulation of Pain Gut Regulation

Question 32

Function: Glutamate

Answer 32

General Excitation | General Sensation

Question 33

Function: Glycine

Answer 33

General Inhibition

Question 34

Function: GABA

Answer 34

General Inhibition

Question 35

Effect: Tetanus Toxin

Answer 35

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

Question 36

Effect: Botulinum Toxin

Answer 36

Inhibits muscle contractions

Question 37

Botulinum types and where they bind

Answer 37

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

Question 38

Effect: Conotoxin

Answer 38

Acts on synapses | Treatment for pain and seizures in epileptic patients

Question 39

Define: Ionotropic Receptors

Answer 39

Contain ion channels that allow passage of specified ions through membrane "Fast" Synaptic Transmission

Question 40

Define: Metabotropic Receptors

Answer 40

Coupled to G-Protein that serves as second messengers that affect ion channels "Slow" Synaptic Transmission

Question 41

Fast synaptic transmission uses what receptors?

Answer 41

Ionotropic Receptors

Question 42

Slow synaptic transmission uses what receptors?

Answer 42

Metabotropic Receptors