Neurocytology I Flashcards Preview

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Flashcards in Neurocytology I Deck (90)
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1
Q

The PNS and CNS are composed of

A

Neurons and Support cells

2
Q

Ganglia (groups of neuron cell bodies), nerves, nerve endings, receptors on neurons or on peripheral targets (skeletal muscle, smooth muscle, etc)

A

Peripheral Nervous System (PNS)

3
Q

What are two examples of PNS support cells?

A

Satellite cells and Schwann cells

4
Q

Nuclei (groups of neuron cell bodies) or cortices (sheets of neuronal cell bodies), nerves, nerve endings, receptors on neurons (or on glia)

A

Central Nervous System

5
Q

What are four support cells of the CNS?

A

Oligodendrocytesm Astrocytes, Ependymal Cells, and Microglia

6
Q

The first evidence of a nervous system is detected during the

A

3rd week in development

7
Q

The ectoderm in the dorsal midline thickens to form the

A

Neural Plate

8
Q

The neural plate gives rise to the

A

CNS

9
Q

Develops from the region lateral to the neural plate and gives rise to the PNS

A

Neural Crest

10
Q

Develops into the brain and spinal cord (CNS)

A

Neural tube

11
Q

The neural tube initially consists of an

A

Epithelium with cilia

12
Q

Give rise to neurons and glia of the CNS

A

Epithelium

13
Q

Provide guidance to migrating neurons and growth factor support

A

Glial cells

14
Q

It is important to note that neurons stop dividing when they

A

Differentiate

15
Q

Can not regenerate if injured by environmental toxins, stroke, or unknown factors leading to degenerative diseases

A

Neurons

16
Q

Functions to receive, integrate, conduct, and transmit information

A

Neuron

17
Q

Neurons vary tremendously in appearance and in

A

Transmitter content

18
Q

The dendritic and somal membrane serves and integrating function by

A

Summing excitatory and inhibitory information that reaches neuron

19
Q

In a neuron, information is received at contact points called

A

Synapses

20
Q

Has the highest concentration of voltage sensitive ion channels and the lowest threshold for firing action potentials

A

Initial axonal segment

21
Q

Presynaptic neurons communicate signals with post synaptic neurons via

A

Synapses

22
Q

Synthesizes proteins and contains the Nissl Bodies (ribosomes and RER)

A

Neuronal cell body (soma)

23
Q

The cell body provides protein to support the

A

Axon

24
Q

The axon is entirely dependent on the cell body for essential materials such as

A

Proteins

25
Q

The axon lacks

A

Nissl bodies

26
Q

The extensions of the cell body and contain most of the organelles of the cell body

A

Dendrites

27
Q

Cytoskeletal elements are found throughout the neuron including in the

A

Axon

28
Q

Contains cytoskeletal elements but no Nissl bodies

A

Axon

29
Q

Axonal transport can occur in which two directions?

A

Anterograde and Retrograde

30
Q

From cell body to the axon terminal

A

Anterograde

31
Q

From axon terminal to the cell body

A

Retrograde

32
Q

Associated with anterograde AND retrograde transport

A

Fast axonal transport

33
Q

Moves such constituents as synaptic vesicles, endosomes, and mitochondria

A

Fast axonal transport

34
Q

Anterograde transport can also be slow and transport things such as elements of the cytoskeleton and proteins such as

A

Clathrin

35
Q

Can also be slow

A

Anterograde transport

36
Q

Fast transport in the anterograde or retrograde direction is associated with

A

Microtubules

37
Q

The “motor” for anterograde transport and in some rare cases, for retrograde transport

A

Kinesin

38
Q

The “motor” for retrograde transport

A

Dynein

39
Q

Although it has been most studied in axons, transport also occurs in

A

Dendrites

40
Q

Play a support function and help regulate axonal growth

A

Intermediate filaments and microfilaments

41
Q

Associated with synaptic vesicle release

A

Microfilaments

42
Q

Spacially discrete membrane specializations which function to mediate communications between neurons and target cells

A

Synapses

43
Q

What are the two types of synapses?

A

Electrichal and chemical

44
Q

Relatively rare in humans and correspond to gap junctions

-seen exclusively during development

A

Electrical synapses

45
Q

In electrical synapses, small pores allow ions and molecules like ATP or small signalling molecules to pass from

A

One cell to the next

46
Q

Made up of a presynaptic element, a synaptic cleft, and a post synaptic element

A

Chemical Synapse

47
Q

Utilizes neurotransmitter molecules

A

Chemical synapses

48
Q

The area in the presynaptic neuron where there is an accumulation of neurotransmitter-filled vesicles

A

Active zone

49
Q

Neurotransmitters are released from vesicles in the presynaptic neuron into the synaptic cleft by way of

A

Exocytosis

50
Q

Vesicles collect in active zones and release their contents when

A

Action potentials invade the terminal

51
Q

Vesicle release from the presynaptic neuron into the synaptic cleft requires

A

Ca2+ influx

52
Q

Binds neurotransmitter vesicles to actin filaments and other components of the cytoskeleton

A

Synapsin I

53
Q

Synapsin I is phosphorylated by a

A

Ca2+/calmodulin dependent kinase

54
Q

What happens when synapsin I is phosphorylated by Ca+2 / calmodulin dependent protein kinase?

A

Vesicles released from actin and move to active zone

55
Q

Docking and fusion of vesicles with presynaptic membrane appears to be associated with multiple proteins including

A

VAMPs and t-SNAREs

56
Q

Calcium sensing proteins such as synaptotagmins are thought to regulate the

A

Docking and fusing process

57
Q

What are the four fates of neurotransmitters in the synaptic cleft that have not bound to the postsynaptic neuron?

A
  1. ) degraded by enzymes
  2. ) taken back up by pre-synaptic terminal
  3. ) taken up by glia
  4. ) diffuse away
58
Q

After transmitter release, exocytotic vesicles remain associated with the plasma membrane and are

A

Recycled

59
Q

After endocytosis, coated vesicles pinch off from the presynaptic membrane, the coat is lost, and the vesicles fuse with the

A

Early endosome

60
Q

In some cases vesicles may be refilled with transmitter without going through the

A

Early endosome pathway

61
Q

Can not be used indefinitely. Some is retrogradely transported and degraded by lysosomes in the cell body

A

Vesicle membrane

62
Q

Neurotransmitter is synthesized and stored in vesicles. Then an action potential invades the presynaptic neuron and causes

A

Depolarization of presynaptic terminal resulting in Ca2+ influx

63
Q

Causes vesicles to fuse with presynaptic membrane

A

Ca2+ influx

64
Q

Causes excitatory or inhibitory postsynaptic potential that changes the excitability of the post synaptic cell

A

Postsynaptic Current

65
Q

Some diseases and chemicals with which we may come into contact can affect aspects of

A

Synaptic transmission

66
Q

Results in impaired vesicle recycling

A

Congenital myasthenic syndromes

67
Q

Attacks presynaptic Ca2+ channels

A

LEM

68
Q

Affect SNARE proteins involved in vesicle fusion

A

Botulinum and tetanus

69
Q

We focused on synapses that are between an axon and a dendrite. There are also

A

Axo-somatic, axo-axonic, and dendro-dendritic synapses

70
Q

There are synapses with a cleft of 400nm and no recognizable densities in the

A

ANS

71
Q

A highly polarized cell

A

Neuron

72
Q

In most cases, each region of a neuron is specialized to contribute to the neuron’s function of

A

Receiving, integrating, and transmitting information

73
Q

Generally the regions of the neuron that receive synaptic signals are

-synaptic signals can be found on other parts of the neuron

A

Dendrites

74
Q

If the neuron is cut off from its source of trophic substances or if an axon is cut off from the cell body it is in danger of

A

Dying

75
Q

In the PNS, groups of neuronal cell bodies are called

A

Ganglia

76
Q

In the CNS, groups of neuronal cell bodies are called

A

Nuclei

77
Q

Provide structural support for migrating neurons and also provide growth factors

A

Glial cells

78
Q

The cell body (soma) can also be referred to as the

A

Trophic locus of the cell

79
Q

Increase surface area of dendritic branches

-are extended in an active cell and retracted in an inactive cell

A

Dendritic Spines

80
Q

What are the three main types of dendritic spine presynaptic membranes?

A
  1. ) Ion channels
  2. ) G-protein linked receptors
  3. ) Kinase receptors
81
Q

Affect polarity of membrane

A

Ion channels

82
Q

The cell body (trophic locus) of a neuron has an extensive

A

RER and ribosomes (Nissl bodies)

83
Q

Nissl bodies extend into

A

Dendrites

84
Q

Organneles move through the axon on microtubules, but in order to reach the terminal, they are transferred to

A

Actin filaments

85
Q

Gap junctions that are typically only present during development

A

Electrical synapses

86
Q

Invaginations in the post synaptic membrane across from vesiccles

A

Junctional folds

87
Q

Phosphorylates synapsin I and allows docked vesicles to move from the actin filament to the presynaptic membrane

A

Ca2+/calmodulin dependent kinase

88
Q

Produced by target cells and released from postsynaptic membranes where they are taken up in vesicles at pre-synaptic membranes

A

Growth factors

89
Q

Growth factors are taken up in vesicles called signaling endosomes, which exhibit which type of transport?

A

Retrograde transport

90
Q

If a lesion causes the cell body to lose it’s growth factors it undergoes

-Nissl bodies move to periphery and disintegrate

A

Chromatolysis

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