Synaptic Physiology I Flashcards Preview

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Flashcards in Synaptic Physiology I Deck (77)
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1
Q

The summation of excitatory and inhibitory potentials in neurons is called _____.

A

synaptic integration

2
Q

What is facilitation?

A

residual Ca++ builds up inside the nerve terminal from previous APs to allow increased strength of new APs

3
Q

This is the spontaneous exocytosis of a single synaptic vesicle.

A

MEPP (Miniature End Plate Potentials)

4
Q

What is the strength of the NMJ synapse?

A

strong

5
Q

Drugs like amphetamine, cocaine, and Prozac exert their actions by _____ of monamine transmitters like dopamine and serotonin.

A

blocking reuptake

6
Q

What is synaptic depression?

A

depletion of releasable synaptic vesicles, reducing the strength of new APs

7
Q

What would happen without the sodium channels at the NMJ?

A

total paralysis bc the depolarization wouldn’t spread

8
Q

What is synaptic integration?

A

the summation of excitatory and inhibitory potentials in neurons

9
Q

What is exocytosis?

A

the process of vesicle and surface membrane lipid fusion to create a pore by which the NT can diffuse out of the cell

10
Q

What does MEPP stand for and what does it mean?

A

Miniature End Plate Potentials; the spontaneous exocytosis of a single synaptic vesicle

11
Q

Name 2 kinds of diseases that weaken the NMJ synapse.

A
  • those that reduce the amount of NT secreted
  • those that block ACh receptor
12
Q

Drugs like ____, ____, and ____ exert their actions by blocking reuptake of monamine transmitters like dopamine and serotonin.

A

amphetamine, cocaine, and Prozac

13
Q

What is the speed of the NMJ synapse?

A

fast

14
Q

Drugs like amphetamine, cocaine, and Prozac exert their actions by blocking reuptake of monamine transmitters like ____ and _____.

A

dopamine and serotonin

15
Q

In the CNS the major excitatory NT is ____.

A

glutamate

16
Q

What is the “intelligence” of the CNS?

A

smart

17
Q

What is the effect of the NMJ synapse?

A

excitatory

18
Q

Slow synaptic transmission is called _____.

A

neuromodulation

19
Q

Name 2 types of Ca++ pumps in the plasma membrane.

A
  1. primary active transporter
  2. Na+/Ca++ exchanger (antiporter)
20
Q

How long does synaptic vesicle recycling take?

A

a few seconds in a well-rested synapse; a few minutes in a hard working one

21
Q

This is the process of vesicle and surface membrane lipid fusing to create a pore by which the NT can diffuse out of the cell.

A

exocytosis

22
Q

Motor neurons in the spinal cord send myelinated axons through _____ and _____ to connect with skeletal muscle fibers.

A

ventral roots; peripheral nerves

23
Q

Virtually every psych drug in use today work specifically at _____.

A

synapses

24
Q

_____ selectively blocks inhibitory synaptic transmission to produce a powerful, persistent, involuntary skeletal muscle contraction.

A

Tetanus toxin

25
Q

The main channel opened by glutamate is _____.

A

an NSC channel

26
Q

What is the “intelligence” of the NMJ?

A

stupid

27
Q

This is the product of the stimulation of the excitatory input that causes depolarization.

A

excitatory post-synaptic potential (EPSP)

28
Q

A decrease in K+ ion permeability of the post-synaptic membrane = ______.

A

depolarization

29
Q

What is the resting membrane potential of a muscle fiber?

A

-80mV

30
Q

What is the threshold for an AP in a muscle cell?

A

-50mV

31
Q

What is the motor end plate?

A

the end of the motor axon where it loses its myelin sheath and splays onto the muscle fiber

32
Q

What is myasthenia gravis?

A
  • an autoimmune disease
  • Abs to ACh receptors
  • results in profound weakness upon exertion
33
Q

What is the NT for the CNS synapse?

A
  • ACh
  • glutamate
  • GABA
  • 5-HC
  • dopamine
  • aspartate
  • glycine
  • ATP
  • histamine
  • NE
34
Q

Ca++ ions that flowed into the motor nerve terminal will be _____.

A

pumped out of the cell

35
Q

These are small protuberances from dendrites that make synaptic contact with incoming axon terminals.

A

dendritic spines

36
Q

What is the NT for the NMJ synapse?

A

ACh

37
Q

Where does AChE come from?

A

the synaptic cleft

38
Q

A single motor axon innervates ____ muscle fibers.

A

many

39
Q

This is an enzyme that cleaves ACh, producing acetate and choline.

A

AChE

40
Q

What does GABA do?

A

it increases chloride permeability in the postsynaptic membrane

41
Q

Name 3 mechanisms for clearing NTs from the synaptic cleft.

A
  1. diffusion
  2. recycling (pumped out)
  3. destruction
42
Q

When does depolarization at the NMJ begin?

A

when ACh-gated channels are activated

43
Q

What is AChE?

A

acetylecholine esterase; an enzyme that cleaves ACh, producing acetate and choline

44
Q

The ACh receptor is a _____ channel.

A

ligand-gated ion

45
Q

What happens if the safety factor of the synaptic transmission is reduced?

A

neuromuscular transmission can fail during repetitive activity–> muscle weakness

46
Q

Where is the trigger zone? What does it do?

A

btw the cell body and the axon; it’s where APs arise

47
Q

What is the effect of the CNS synapse?

A

excitatory OR inhibitory

48
Q

An AP in the inhibitory terminal releases ____, which opens Cl- channels in its target presynaptic terminal.

A

GABA

49
Q

Where do APs always arise from?

A

the trigger zone

50
Q

Name 2 receptors that ACh acts upon in the CNS.

A
  • nicotinic
  • muscarinic
51
Q

A skeletal muscle receives synaptic input from ____ motor neuron.

A

one

52
Q

What is the transmitter termination for the NMJ?

A
  • diffusion
  • degradation by esterase
53
Q

The major inhibitory NT in the CNS is _____.

A

GABA

54
Q

What are dendritic spines?

A

small protuberances from dendrites that make synaptic contact with incoming axon terminals

55
Q

What is the speed of the CNS synapse?

A

fast OR slow

56
Q

This is when residual Ca++ builds up inside the nerve terminal from previous APs to allow increased strength of new APs.

A

facilitation

57
Q

Post-exocytic vesicles are retrieved by the formation of ______.

A

clathrin coated pits

58
Q

This is the end of the motor axon where it loses its myelin sheath and splays onto the muscle fiber.

A

the motor end plate

59
Q

What is the difference btw Myasthenia gravis and myasthenic syndrome?

A
  • Myasthenia gravis = post-synaptic block
  • myasthenic syndrome = pre-synaptic block
60
Q

Why do APs arise at the trigger zone?

A

the threshold is lower here bc of the high density of voltage-gated Na+ channels

61
Q

An AP in the inhibitory terminal releases GABA, which ______ in its target presynaptic terminal.

A

opens Cl- channels

62
Q

What happens to ACh?

A
  • it diffuses out it’s destroyed by ACh0
  • it is re-taken up
63
Q

Why is the ACh-gated ion channel called a Non-Selective Cation (NSC) channel?

A

it is permeable to ALL cations

64
Q

Binding of ACh (the ligand) opens the gate and Na+ ions flow into the muscle fiber to _____ it.

A

depolarize

65
Q

CNS neurons receive synaptic input from _____ neurons.

A

many

66
Q

What is the strength of the CNS synapse?

A

weak

67
Q

In skeletal muscle only, the postsynaptic membrane is _____ to increase surface area.

A

folded

68
Q

Dx?

  • an autoimmune disease
  • Abs to ACh receptors
  • results in profound weakness upon exertion
A

Myasthenia gravis

69
Q

How does the AP propogate all the way to the tendon?

A

voltage-gated Na+ channels open in both directions away from each other

70
Q

The binding of Ca++ triggers the fusion of ____ of the vesicle and surface membranes, opening a _____.

A

lipids; fusion pore

71
Q

A single AP in the motor axon causes every muscle fiber to twitch ____.

A

once

72
Q

This is the depletion of releasable synaptic vesicles, reducing the strength of new APs.

A

synaptic depression

73
Q

What is the transmitter termination for the CNS?

A
  • reuptake
  • diffusion
74
Q

What is an EPSP?

A

an excitatory post-synaptic potential; product of the stimulation of the excitatory input that causes depolarization

75
Q

A postsynaptic response can be either ____ or ____.

A

excitatory; inhibitory

76
Q

Binding of ACh (the ligand) opens the gate and ____ ions flow into the muscle fiber to depolarize it.

A

Na+

77
Q

During repetitive nerve stimulation, what 2 important and opposing changes occur in the presynaptic terminal?

A
  • the Ca++ ion concentration builds up
  • the pool of releasable vesicles is depleted