Nervous Tissue Flashcards

1
Q

what is the structural and functional unit of the nervous system?

A

neuron

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2
Q

what do neurons constitute? (3)

A

most sensory receptors
conducting pathways
integration centers

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3
Q

where are most neuron cell bodies located?

A

CNS

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4
Q

all neurons terminally differentiated (Go)…

A

do not divide, although regeneration of axons is possible

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5
Q

what are the two basic cell types of nervous tissue?

A
neurons
supporting cells (non-conducting)
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6
Q

what do supporting cells provide? (3)

A

physical support snd protection
electrical insulation
metabolic exchange

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7
Q

3 categories of supporting cells

A

neuroglia in CNS
Schwann cells in PNS
stellate cells in ganglia

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8
Q

soma contains

A

nucleus surrounded by cytoplasm

cell body

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9
Q

perikaryon

A

area around the nucleus

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10
Q

Kissel substance

A

rough ER

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11
Q

neurilemma

A

plasma membrane surrounding the cell

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12
Q

melanin, lipofuscin

A

age pigment within the cell body

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13
Q

neuronal dendrites

A

one or more highly branched neuron processes

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14
Q

dendrites receive stimuli from

A

other neurons or environment (afferent)

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15
Q

single axon

A

transmits stimuli to other neurons or effector cells (efferent)

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16
Q

axon arises from

A

Saxon hillock

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17
Q

axon hillock terminates in the distal swelling called the

A

terminal bouton

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18
Q

axonal transport

A

movement of products down the axon

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19
Q

slow axonal transport carries

A

cytoskeletal elements

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20
Q

fast exon transport carries

A

membrane bound organelles

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21
Q

anterograde transport

A

from cell body down the axon

used kinesis

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22
Q

retrograde transport

A

from axon to cell body

uses dynein

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23
Q

multi-polar neuron

A

most common, several dendrites

ex. motor neurons, interneurons

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24
Q

bipolar

A

single dendrite opposite axon

ex. receptor neurons of retina

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25
Q

unipolar

A

no dendrites on soma, axon only

ex. sensory neurons

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26
Q

pseudo unipolar

A

insult dendrite and axon fuse, soma off to one side

ex. dorsal root ganglion

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27
Q

Na+ and Cl- are higher – the cell

A

outside

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28
Q

K+ is higher – the cell

A

inside

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29
Q

resting membrane potential inside the cell

A

~80 mV

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30
Q

action potential is an – or none response

A

all

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31
Q

action potential arises in the cell body as a result of an

A

affect stimulus

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32
Q

causes region of the plasma membrane to

A

depolarize

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33
Q

causes reversal of resting potential, cells electrical potential

A

neutralized (goes to zero, or slightly positive)

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34
Q

during the refractory period,

A

na+ channels close and can’t reopen for another 1-2 msec

Na+ is unresponsive to the stimuli

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35
Q

refractory period is initially —, where response to stimulus is impossible, then —, where only a very strong stimulus can initiate depolarization

A

absolute

initial

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36
Q

after Na channels close, voltage hated K channels also close, membrane depolarizes, ends

A

refractory period

37
Q

opening and closing of na and k channels in a domino effect along the axon, the change in electrical potential of the membrane which travels down the axon as a

A

wave of depolarization

38
Q

action potential is then conducted to effector cell at the synapse via

A

neurotransmitter

39
Q

what are synapases/neuromuscular junctions?

A

specialized junctions between neurons or between neuron and effector cell
(ex. mm)

40
Q

each synapse is —

A

unidirectional

41
Q

response to stimulus max be either

A

excitatory or inhibitory

42
Q

entrainment

A

more a pathway is used, easier it is to access

43
Q

terminal bouton separated from the effector cell via the

A

synaptic cleft

44
Q

what does the synaptic cleft contain?

A

mitochondria and membrane bound semantic vesicles containing neurotransmitters

45
Q

signaling molecules are related from the

A

presynaptic membrane

46
Q

diffuse across the synaptic cleft, bind to receptors on the

A

postsynaptic membrane

47
Q

neurotransmitters used in the PNS

A

acetylcholine

norepinephrine (adrenaline)

48
Q

sympathetic uses

A

noradrenaline (norepinephrine) as excitatory neurotransmitter (adrenergic)

49
Q

parasympathetic uses

A

actyelcholine as the excitoru neurotransmitter (cholinergic)

50
Q

vesicles on the post unapt membrane contain hydrolytic and oxidative enzymes such as (2)

A

acetylcholinesterase

MAO

51
Q

inactive neurotransmitter between consecutive impulses prevents

A

continuous stimulation

ex. tetany

52
Q

pns contains

A

afferent or efferent (axons) of either somatic or autonomic nn

53
Q

cell bodies of PNS are located in

A

CNS or ganglia

54
Q

peripheral nerve bundle

A

fascicle

55
Q

Schwann cells derived from neural crest associated with axons provide

A

metabolic support and electrical insulation

56
Q

nuclei along the length of the axon belong to

A

schawnn cells

57
Q

in the PNS, all Nn enveloped by

A

Shawnee cells

58
Q

Schwann cells provide

A

structural and metabolic support

59
Q

in non myelinated Nn several axons lie in channels within Shawnee cells, surrounded by a single layer of

A

neurilemma from Schwann cells

60
Q

myelinated Nn insulated by many concentric layers of plasma membrane from many

A

Schwann cells

61
Q

the sachets of Schwann consists mostly of cell membrane and forms the

A

myelin sheath

62
Q

many axons found together in a fascicle form a

A

nerve

63
Q

nodes of ranvier

A

gaps in myelin sheath between adjacent Schwann cells

64
Q

nodes of ranvier are responsible for

A

rapid, saltatory conduction

65
Q

membrane depolarization only occurs as —, not beneath Schwann cell, faster conserves electrolytes

A

nodes

66
Q

myelinated Nn in the CNS sheathed by cells called

A

oligodendrocytes

67
Q

one oligodendrocyte surrounded several NN with >1 layer of

A

plasma membrane

68
Q

rate of conduction is proportional to the diameter of

A

the axon
(bigger=faster)
Myelin increases conduction rate

69
Q

individual axons and Schwann cells are surrounded by loose connective tissue called the

A

endoneyrium

70
Q

multiple axons are organized into bundles called fascicles surrounded by

A

perineurium

71
Q

small diameter of Nn containing only one fascicle surrounded by

A

perineurium

72
Q

cells of the perineurium are

A

unique, not just fibroblasts

73
Q

;arger Nn containing several fascicles are surround by an additional layer of connective tissue called the

A

epineurium

74
Q

blood vessels tend to follow

A

epi and peri neurium

75
Q

cells of the perineurium exhibit — and — features. may play a role in axon regeneration

A

epitheliod and myoid

76
Q

in the ANS, - neurons connect the CNS t viscera

A

2

pre and post ganglionic neurons

77
Q

preganglionic neurons have cell bodies in the

A

gray matter of the brain and cord in CNS

78
Q

preganglionic axons synapse with

A

postganglionic

79
Q

postganglionic cell bodies are found within

A

ganglia

80
Q

ganglia

A

discrete aggregations of postsynaptic neuron cell does located out the CNS

81
Q

embryologically derived from the neural crest, like all

A

peripheral nn

82
Q

each cell body (soma) is surrounded by

A

satellite cells

83
Q

satellite cells are derived from

A

neural crest

84
Q

satellite cells provide

A

structural and metabolic support

85
Q

location of autonomic ganglia varies

A

sympathetic ganglia parallel to vertebral column

parasympathetic ganglia lie in or near the effector organ

86
Q

sympathetic ganglia include – and – ganglia

A

prevertebral and paravertebral

87
Q

prevertebral ganglia are located

A

anterior to the spine

88
Q

paravertebral ganglia are located primarily in the

A

sympathetic trunk

89
Q

parasympathetic ganglia are located

A

in or near the effector organ