nervous system Flashcards

(64 cards)

1
Q

what is nervous tissue composed of

A

100 billion neurons and trillions of glial support cells

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2
Q

what does classification of nervous tissue depend on

A

differ in types of cells

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3
Q

describe nervous tissue classification anatomically

A

cns = brain, cerebellum, spinal cord = gray and white matter, can distinguish between
pns = nerve ganglia, nerve fibers

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4
Q

describe nervous tissue classification histologically

A

nerons - nerve cells
neuroglia - glial cells equivalent to the ct = involved in support, neuron protection, defense and nutrition

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5
Q

what is difference between CNS gray matter and white matter

A

gray = cell bodies of neurons, neuroglia
white = neuronal cell processes (axons), neuroglia

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6
Q

what is neuron

A

functional unit of nervous system

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7
Q

what does neuron consist of

A

dendrites
cell body
axons

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8
Q

describe dendrites

A

Receives signals
neurons synapse with each other and other things

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9
Q

describe cell body

A

integrates incoming signals from dendrites and outgoing signals to axons
soma, perikaryon
organelles and nucleus

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10
Q

describe axons

A

transmits signals to another neuron or effector cell

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11
Q

what is present in grey matter cns and ganglia pns

A

dendrites and cell bodies

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12
Q

what is present in white matter cns and nerve fiber pns

A

axon

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13
Q

what are the dots

A

nissl bodies

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14
Q

how to tell axon from dendrite

A

dendrites still have nissl bodies
axon hillock has no nissl bodies at begining of axon

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15
Q

do all nerons look the same

A

neurons have complex moprhology
perikaryons can be spherical, ovoid or angular
can have more than 2 processes = multipolar
not all neurons are typical and many have multiple polarities

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16
Q

name and describe types of neurons

A

pyramidal - brain cortex
purkinje - cerebellum
motor neurons - spinal cord
pseudounipolar - spinal ganglia, bifurcates- opens in 2, arborizes, branches
bipolar = retinal, olfactory, mucosa, originates from same cell body then goes in 2 opposite directions

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17
Q

name parts of cns

A

cerebrum
cerebellum
spinal cord

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18
Q

what does cns show when sectionned

A

regions of white or grey matter when sectioned

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19
Q

what does gray matter have

A

neuronal cell bodies and neuroglial cells

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20
Q

what does white matter have

A

axons and neuroglial cells
appears white due to presence of myeline around myelinated axons

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21
Q

where is cerebrum

A

upper portion of brain

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22
Q

what is function of cerebrum

A

integration of sensory information (from peripheral nervous system= sensory modalities = olfactory,touch, language,learning,nearing
initiation of voluntary motor Responses - motor cortex

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23
Q

describe histology of cerebrum

A

white matter appears lighter
gray matter appears darker, more homogenous

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24
Q

describe white matter of cerebrum

A

both longitudinal and cross section
broken up appearance
where myelin used to be - white spaces, does not preserve well

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25
describe gray matter of cerebrum generally
can trace where axons are entirely different no myeline since no axons cell bodies and nucleus smaller = neuroglial cells in white and gray mater = support cells, maintains, supports and protects tissue
26
describe gray matter of cerebrum specifically
6 layers in cerebral cortex pyramidal neurons are most prominent - pyramidal shaped, arranged in paralel with another, larger than glial cells, see bulky cell bodies
27
where is cerebellum found
part of hindbrain
28
describe function of cerebellum
integration of sensory information (from PNS) Fine tunes voluntary motor Responses = integrate and refine info for complex movement
29
describe damage or lesions to cerebellum
can still do voluntary movement but harder and worse less fine tined, poor balance, posture, harder to learn fine movements
30
describe histology of cerebellum
cerebellar cortex - gray matter has 3 layers = molecular purkinje granular
31
describe molecular layer of cerebellum
sparse neurons
32
describe purkinje layer of cerebellum
very large neruons dendrites project into molecular layer axons project into granular layer
33
describe granular layer of cerebellum
very small densely packed neurons axons are unmyelinated = project into molecular layer where they synapse with dendrites of purkinje cells
34
what is function of spinal cord
relay messages from brain to body pass sensory info from sensory receptors to brain coordinate reflexes that are managed by spinal cord alone - like patellar/knee jerk reflex
35
describe white and gray matter of spinal cord
white = white spaces, cord bundles, relatively all circular - can say its cross section gray matter = have cell bodies
36
name parts of pns
somatic autonomic
37
describe somatic system
sensory nerve fibers that send sensory info to CNS afferents - Receives processes & integrates ·motor fibers that project from CNS to skeletal muscle (efferent)- away through spinal cord through motor nerve fibers
38
describe autonomic system
controls smooth muscle of internal organs and glands involuntary
39
what is pns - which cells
ganglia - grouping of cell bodies nerve fibers - bundles axons, H&E staining
40
where are cell bodies located of pns and cns
sensory and autonomic neurons have cell bodies in ganglia neuron cell bodies of motor neurons are located in spinal cord
41
what forms myelin
oligodendrocytes in cns schwann cells in pns
42
what is myelin like
lipoprotein
43
are all axons myelinated
NOOO
44
what is function of myelin
electrical insulation faster conduction of nerve impulse
45
what are nodes of ranvier
gaps between myeline sheath that promote transmission of ap
46
when is axonal conduction faster
axonal conduction of nerve impulse is faster in myelinated axons and even faster in axons with thicker myelin sheath
47
describe myelination in cns
oligodendrocytes in cns white matter produce myelin sheath several axons myelinated by one individual oligodendrocytes = wraps around and around - concentric layers of myelin = myelin sheath
48
what is myeline sheath
several layers of modified cell membrane containing lipoprotein called myelin
49
what is myelin composed of
phospholipids sphingolipids proteins = myeline basic protein, MP2 etc
50
what does autoimmune response against myeline result in
demyelination MS landry guillain barre etc
51
describe myelination in PNS
schwann cells produce myelin sheath one axon is myelinated by one shcwann cell
52
where does axon begin and end
beings at axon hillock ends in terminal arborizations and end bulbs called terimal boutons which are apart of synapses
53
what does terminal bouton depend on
depends on goal of info
54
what can synapses form between
axon and dendrite axon and cell body axon and axon
55
synapses can be....
excitatory or inhibitory
56
what are neuroglia
Multiple different cell types with different roles, supports neurons in different ways neuroglial cells provide support, protection and nutrition to neurons
57
name 3 kinds of neuroglia
astrocytes oligodendrocytes microglia
58
describe astrocytes - what
largest neuroglial cells found in white matter of cns has pedicles or vascular feet
59
describe oligodendrocytes - what
found in gray and white matter of cns
60
describe microglia - what
scattered throughout cns smallest neuroglial cells darkly stained derive monocytes
61
describe astrocytes - function
form and maintain blood brain barrier removes ions and neurotransmitter remnants like GABA and glutamate
62
describe oligodendrocytes - function
satellite cells around neurons in CNS are oligodendrocytes in white matter = produce myelin Specialized function = support neuron , make synapse quicker and faster and insulate conduction of nerve
63
describe microglia - function
function as phagocytes clearing debris of damaged structured in cns
64
what are processes
axons and dendrites