Lectures 8-9: Nervous Tissue I And II Flashcards
(101 cards)
1
Q
main functions of nervous tissue (3)
A
-coordinate body function with internal/external environment
-coordinate and integrate cellular signals
-long distance communication
2
Q
2 types of neurons
A
-sensory input
-motor output
3
Q
sensory input neurons aka
A
afferent
4
Q
afferent means
A
carrying towards a center
5
Q
efferent means
A
carried away from
6
Q
sensory input neurons carry what kind of info
A
brought from periphery to cns
7
Q
motor output neurons carry what kind of info
A
leave cns for periphery
8
Q
skeletal muscle is an example of what kind of neuron
A
motor output/efferent
9
Q
examples of sensory input/afferent neurons
A
proprioceptive, pain, temperature, touch
10
Q
how is nervous system organized
A
-central
-peripheral
11
Q
2 parts of cns (general)
A
-brain
-spinal cord
12
Q
2 parts of pns (general)
A
-cranial nerves
-spinal nerves
13
Q
2 parts of cns (structural)
A
-gray matter and nuclei
-white matter and tracts
14
Q
2 parts of pns (structural)
A
-ganglia
-nerves
15
Q
functional unit of nervous system
A
neuron
16
Q
3 types of neurons(morphology)
A
-multipolar
-bipolar
-pseudounipolar
17
Q
majority of axons are what morphological type
A
multipolar
18
Q
glial cells definition
A
cells that support neurons
19
Q
what are the 2 fundamental cells in nervous tissue
A
neurons and glial cells
20
Q
neuropil definition
A
synaptically dense regions composed of unmyelinated axons, dendrites and processes of glial cells
21
Q
is there any connective tissue within cns
A
no
22
Q
primary function of neuron
A
generate and propagate action potentials
23
Q
what kind of signals do neurons receive
A
chemical and electrical
24
Q
anatomy of basic neuron (8)
A
-dendrites
-cell body
-axon hillock
-initial segment
-internodal segment
-node of ranvier
-terminal arborizations
-terminal boutons
25
what is the first part of the axon where the action potential begins
initial segment
26
dendrites function
receive info from other neurons and carry info to the cell body
27
cell body aka
perikaryon
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function of dendritic spines
-increase surface area
29
what can dendrites change about their membranes
membrane potential of membrane
30
what structures do neuron cell bodies contain that dendrites and axons don't
-cell body contains nissl bodies, golgi complexes and nucleus
31
what passes from cell body to axon
cytoskeleton and secretory vesicles
32
where are action potentials generated
initial segment
33
7 components of neuron cell body: organelles and structures
-nucleus
-nucleolus
-nissl bodies
-golgi complex
-mitochondria
-neurofilaments
-microtubules
34
function of golgi complexes in neuron
produce regulated synaptic vesicles to package and deliver neurotransmitter to end of axon
35
what are contained within nissl bodies
rough ER and ribosomes
36
neurofilaments in axon: definition and function
-intermediate filaments
-stability/structure
37
function/definition of microtubules in axon
-grow and shrink to move material around (from and to)
38
function of myelin
insulate cells during propagation of signal
39
Length of axons vs dendrites
Axons much longer (up to meters long)
40
Axonal transport is ____________ (directional term)
Bidirectional
41
Axonal transport: 2 directions
-anterograde
-retrograde
42
Anterograde axon transport
-Away from cell body
-transport synaptic vesicle protein down axon for potential exocytosis release
43
Is anterograde axon transport fast or slow
Can be either
44
Retrograde axon transport
-toward cell body
-cell membranes returned to cell body for reuse or degradation
45
Is retrograde axon transport fast or slow
Fast
46
Axonal transport: 2 speeds
-fast
-slow
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Axonal transport: fast transport (what is used/transported)
-microtubules and motor proteins (lines in)
-transport organelles, synaptic vesicles
48
Slow anterograde transport
-transports cytoskeleton precursors and elements that contribute to stability of axon
49
4 steps of Axonal transport
-synthesis, assembly and export
-anterograde transport
-release of neurotransmitter
-retrograde transport
50
Where do axons end
Terminal boutons
51
Synapse definition
Connection between neurons for communication
52
Synaptic cleft definition
Cells separated by narrow gap
53
What initiates neurotransmitter release
Action potential
54
Where does neurotransmitter cross
Synaptic cleft
55
Effect of neurotransmitter crossing synaptic cleft
Depolarizes postsynaptic membrane or hyperpolarization
56
4 types of synapses
-axodendritic
-axosomatic
-axoaxonic
-neuromuscular
57
Axodendritic synapse
Between axon of one cell and dendrite of another cell
58
Axosomatic synapse
Between axon of one cell and cell body of another cell
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Axoaxonic synapse
Between 2 axons
60
Neuromuscular synapse
Between motor neuron of one cell and muscular tissue
61
All synapses possess what kind of elements (2)
Pre synaptic and post synaptic
62
Anatomy of synapse
-presynaptic and postsynaptic membrane with synaptic cleft in the middle
-synaptic vesicles surrounding
-mitochondrion
-dendrites
63
Presynaptic element: definition
Axon of 1st neuron
64
What structure contains neurotransmitter
Synaptic vesicles
65
Are synaptic vesicles part of the presynaptic element or postsynaptic element
Presynaptic
66
Postsynaptic element definition
2nd neuron
-postsynaptic density
67
General properties of neurotransmitter reuptake and recycling (3)
-transporter mediated
-recycled enzymatic products
-vesicle is recycled
68
Neuromuscular synapse definition
Release of Ach from motor neuron propagates action potential within muscle fiber
69
Sarcoplasma definition
Plasma membrane of muscle cell
70
Transverse tubules general function
Action potential travels through to reach internal muscle fibers
71
How does action potential travel in neuromuscular synapse
Through sarcolemma and t tubules
72
Sarcolemma
Plasma membrane of muscle cell
73
Sarcoplasmic reticulum
-smooth ER
-stores calcium
74
Neuromuscular synapse: how it works
-depolarization propagates through t tubules to sarcoplasma reticula
-activates calcium channels to release calcium and cause contraction
75
Where do t tubules contact/touch
Terminal cistern are of sarcoplasmic reticulum
76
Ganglia definition
Clusters of cell bodies outside CNS
77
Where are psuedounipolar neurons found
Sensory ganglia
78
How do you know you’re looking at a histological section from the peripheral nervous system
Connective tissue stained blue
79
Satellite cells
Glia that form a complete ring around pseudounipolar neuron cell bodies
80
99% of all neurons are what morphological type
Multipolar
81
2 types of non neuronal cells in nervous system
-glial cells (CNS)
-PNS non neuronal cells
82
4 types of glia
-Astrocytes
-microglia
-Schwann cells
-oligodendrocytes
83
Microglia functions
-remove damaged neurons and infectious agents
-can become phagocytes
-primary immune defense
84
Microglia: PNS or CNS
CNS
85
Astrocytes function/support (3)
-blood brain barrier
-form glia limitans
-proliferation at sites of injury
86
Glia limitans definition
Barrier between pia mater and CNS
87
Schwann cells function
Myelinate PNS axons
88
Oligodendrotytes function
Myelinate CNS axons
89
Schwann cells vs oligodendrotyes
-Schwann cells myelinate 1 single internodal segment forever
-oligodendrocytes Myelinate more than 1 axon
90
What is myelin
Insulating series of glial cell plasma membranes (wrapped around and compressed in a loop around axon)
91
At which parts of axon is myelin absent
-initial segment
-axon terminals
-nodes of ranvier
92
Regions where myelin is present are called
Internodal segments
93
What are unmyelinated axons
-not truly without Schwann cells
-axons are enveloped by glial cell but not wrapped by glial cell
94
Where are unmyelinated axons found (general importance)
In places where conduction speed is not important
95
CNS myelin vs PNS myelin
-CNS myelin made of oligodendrocytes
-PNS myelin made of Schwann cells
96
How do peripheral nerves appear under light microscopy and why
Wavy because body wall moves and nerves have to accommodate for that movement
97
Collections of axons in periphery are called
Peripheral nerves
98
3 layers of connective tissue around peripheral nerve
-epineurium
-perineurium
-endoneurium
99
Epineurium
-around whole nerve and many axons
-very dense, fills space between nerve fibers
-outermost layer
100
Perineurium
Surrounds each bundle of nerve fibers
101
Endoneurium
-Envelops myelin sheath of individual axons
-composed of reticular fibers produced by Schwann cells
