Neurotransmission Flashcards

1
Q

What is contained is presynaptic part?

A

Vesicles containing neurotransmitter

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2
Q

Describe the structure of post-synaptic?

A

Junctional folds with Ach receptors and cholinesterase enzymes

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3
Q

Where is the origin of end plate potentials?

A

At the endplate

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4
Q

What do mini end plate potentials do?

A

Spontaneous release of one packet of neurotransmitter into the synaptic cleft

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5
Q

What is meant by a quantal?

A

Neurotransmitter put into packets

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6
Q

What are EPPs built from?

A

A large quantity of minEPPs

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7
Q

What neurotransmitter produces an EPSP?

A

Acetylcholine

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8
Q

What receptor does Ach fuse to?

A

Nicotinic Ach receptor

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9
Q

How many molecules of Ach are required to activate receptor?

A

2

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10
Q

How does the nicotinic Ach receptor change when the Ach fuses with it?

A

Rearrangment of receptor allows permeation of ions through aqueous pore. Permeable to both Na+ and K+ when opened, depolarising membrane

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11
Q

What receptor type is involved in generating IPSP?

A

Ligand gated chlorine channel

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12
Q

What neurotransmitter is involved in generating IPSPs in the brain?

A

GABA

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13
Q

What neurotransmitter is involved in generating IPSPs in the spinal cord?

A

Glycine

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14
Q

What two changes occur in GABA receptors in the generation of IPSPs?

A
  • Hyperpolarisation of membrane

- Membrane becomes leakier to current so more difficult to generate a current

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15
Q

What stimulus are muscle spindle fibres sensitive to?

A

Stretch (mechanoreceptor)

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16
Q

Describe how monosynaptic reflex works?

A
  • Muscle spindle fibres sends la afferent into spinal cord via dorsal root
  • Synapses in ventral horn to alpha motor neuuron
  • Sends axons to homonymous muscle making synapses with numerous muscle fibres
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17
Q

What is meant by recipricol antagonistic inhibition?

A

When one muscle is flexed, other is inhibited so it can relax

18
Q

How is the antagonistic muscle relaxed?

A

Also well as monosynaptic activation of flexor neuron, there is another synapse onto interneuron in spinal cord.
Synapse is excitatory on inhibitory interneuron which release glycine at its synapse to inhibit antagonistic muscle.

19
Q

What is the difference between neurotransmission, neuromodulation and neurotrophic factors?

A

Neurotransmission: ms
Neuromodulation: takes seconds to minutes
Neurotrophic factors: slowest of all- minutes to hours

20
Q

What type of receptor is used in fast neurotransmission

A

Pentameric and tetrameric receptors that incorporate ion channels

21
Q

What type of receptor is used in neuromodulation?

A

G protein coupled receptor

22
Q

What happens when neuromodulator binds to GPCR?

A

Activates second messenger which causes series of reaction which causes modulation of ion channels

23
Q

Is glutamate fast, modulator or both?

A

Both

24
Q

Is Ach fast, modulator or both?

A

Both

25
Q

Is glutamate fast, modulator or both?

A

Both

26
Q

Is GABA fast, modulator or both?

A

Both

27
Q

Is glycine fast, modulator or both

A

Fast

28
Q

Is 5-HT fast, modulator or both?

A

Both

29
Q

Is noradrenaline fast, modulator or both?

A

Modulator

30
Q

Is dopamine fast, modulator or both?

A

Modulator

31
Q

Where specifically does Ach bind to on channels?

A

C loops

32
Q

Name the 2 mechanisms involved in termination of transmitter?

A

Neurotransmitter breakdown

Neurotranmitter reuptake

33
Q

What enzyme breaks down Ach?

A

Acetylcholinesterase

34
Q

What can inhibit acetylcholinesterase?

A

Organophosphate nerve agents

35
Q

How is glutamate reuptaken?

A

Glutamate transporter reuptakes into neurons and glial cells

Runs of Na+ gradient

36
Q

How is GABA reuptaken?

A

reuptaken into presynaptic terminals and astrocytes by GATs

37
Q

What is M response?

A

direct activation of motor unit by electrical stimulation

38
Q

What is H reflex?

A

Electrical equivelent to stretch reflex

39
Q

What is F wave?

A

Antidromic motor nerve action potentials bouncing off the alpha motor neurons

40
Q

What is the effect of peripheral demyelination?

A

Effects conduction time or number of axons that work

41
Q

What is meant by giant motor unit and what condition is it seen in?

A

Alpha motor neurons die- denervation of motor fibres. surviving motor neurons sprout and send new collaterals to muscle fibres. Large motor units when 1 motor neuron innervates more than usual
ALS