Dr. Chirwa Flashcards

Presynaptic Mechanisms

1
Q

Two types of presynaptic Mechanisms?

A

electrical and chemical

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2
Q

Electrical synapse

A

the movement of electrical current jumping from gap junction to gap junction.

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3
Q

Chemical synapse

A

The movement of neurotransmitters from one neuron to another

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4
Q

Post synaptic neurons

A

Have a slight delay

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5
Q

contains electrical vesicles in the presynaptic neuron

A

chemical synapse

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6
Q

Why does chemical synapse take much longer than electrical synapse?

A

because NT on chemical synapse to to line up with receptors of the post synaptic neuron, then release the presynaptic NT from the synaptic vesicle.

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7
Q

Synaptic vesicle

A

stores NT in vesicles in the presynaptic neuron in chemical synapse.

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8
Q

2 millisecond delay

A

is seen with chemical delay occurs slowly due to neurons aligning releasing and binding of NT

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9
Q

1 millisecond delay

A

seen with electrical delay which occurs quickly through gap junctions

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10
Q

Synapsin

A

anchors group of NT vesicles together

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11
Q

Docking

A

NT being free and going close to the plasmalemma

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12
Q

What must occur before NT vesicles release NTs docked on the plasmalemma?

A

Calcium must enter the neuron through calcium channels.

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13
Q

Clathrin

A

A protein that reclaims back old NT cleaving inward.

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14
Q

Dyanamine protein

A

takes the neck of the Clathrin vesicle so it can be released

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15
Q

At rest the presynaptic terminal is negative or positive.

A

it is negative until an AP occurs the presynaptic terminal becomes more positive (depolarize)

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16
Q

When does depolarization occur?

A

When calcium enter the neuron through calcium channels

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17
Q

What type of cells pick up calcium ions in the synaptic cleft?

A

glial cells

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18
Q

What holds syntaxin and synaptobrevin together?

A

SNAP-25 protein

19
Q

What is the name of the “calcium sensor”?

A

Synaptotagmin

20
Q

What can happen if BoTx or TeTx is injected in the veins?

A

it prevents the binding of syntaxin and synaptobrevin and acetocholine can not bind for a long time which can paralyze the diaphragm because it also needs acetylcholine. Patient will need a ventilator

21
Q

Lambert-Eaton Myasthenic syndrome

A
22
Q

Botulin toxin

A
23
Q

Tetanus Toxin

A
24
Q

Which statement regarding metabotropic and ionotropic receptors is true?

A

Ionotropic receptors have immediate efects; metabotropic receptors
produce long-term efects.

25
Q

Which event is the first in the series of events that take place
during chemical synaptic transmission?

A

Voltage gated Ca2+ channels open

26
Q

In the sequence of events in neurotransmission, which event occurs just after the action potential arrives at the presynaptic terminal?

A

Influx of Ca2+ into the presynaptic terminal

27
Q

How would application of a Ca2+ channel blocker affect the function of a synapse?

A

It would eliminate the postsynaptic potential and the presynaptic Ca2+ current.

28
Q

Which protein plays a key role in endocytosis?

A

Clathrin

29
Q

A scientist wishes to develop a new drug that prevents
synaptic communication via neuropeptides but not small
molecule neurotransmitters. Which mechanism would be a
good target for his drug?

A

Disruption of fast anterograde axonal transport

30
Q

Which treatment would prevent the release of neurotransmitter
from the presynaptic terminal?

A

A toxin that cleaves synaptobrevin

31
Q

Clostridial Toxin

A

Cleaves syntaxin, synaptobrevin, SNAP-25

32
Q

The most important factor determining whether a receptor-operated ion channel is inhibitory or excitatory is

A

whether the permeant ion’s reversal potential is positive or negative to threshold.

33
Q

Which statement about a nicotinic acetylcholine receptor at the
neuromuscular junction is accurate?

A

It has two binding sites, and binding of two molecules ofacetylcholine, one to each site, is required to activate the receptor.

34
Q

Which molecule binds NMDA receptors and prevents the
flow of ions at resting and hyper polarized membrane
potentals?

A

Mg2+

35
Q

Which change could be responsible for increasing the amplitude of an
excitatory postsynaptic potential (EPSP)?

A

An increase in the amount of glutamate released into the synapse

36
Q

Cell X fires an action potential and releases GABA onto Cell Y.
Assuming only GABAA receptors are present on the postsynaptic
membrane, which is at rest at –55mV, which ion is responsible for
the changes that would be observed?

A

Chloride

37
Q

Which statement describes a possible outcome for a neurotransmitter after release into the synaptic clef?

A

Activation of G-protein-coupled receptor on postsynaptic cell

38
Q

Which has more lasting affect Inotropic or Metabotropic receptors?

A

Metabotropic receptors

39
Q

Nicotinic Acetylcholinergic Receptor

A

requires two Ach to bind to its alpha subunit

40
Q

AMPA Receptors

A

activated by glutamate

41
Q

NMDA Receptor

A

activated by glutamate and glycine
Mg2+ is its gate keeper

Depolarization of the membrane kicks Mg2+ out

42
Q

Which receptors produces fast excitatory postsynaptic current

A

AMPA and NMDA

43
Q

Where does the trigeminal nerve enter the brain?

A

mid pons

44
Q
A