L15: Nervous Tissue Flashcards
(120 cards)
1
Q
list the stages of neural development
A
- neural plate
- neural folds
- neural tube
- neural crest tissue
2
Q
list derivatives of neural tube
A
- telencephalon
- diencephalon
- mesencephalon
- metencephalon
- myelencephalon
3
Q
3 histogenesis components of neural tube
A
- pseudostratified epi
- cortical plate
- marginal layer
4
Q
neuroglial cells ?
A
non-conductive cells that support and protect entire nervous system
hold together system
5
Q
cortical plate
A
future gray matter
6
Q
marginal layer
A
axons
future white matter
7
Q
nerve tissue characteristics
A
- irritability
- conductibility
- cellular components
- neurons
8
Q
nerve tissue irritability
A
tissue specialized to receive stimuli
9
Q
nerve tissue conductibility
A
tissue specialized to transmit impulses
10
Q
cellular components of nerve tissue
A
neurons
neuroglial cells
11
Q
neuron functions
A
- -conduct impulses
- -structural and functional unit of nervous system
12
Q
neuron parts
A
cell body = soma
dendrites
axon
terminal boutons
13
Q
neuron cell body
A
- contains nucleus
- Nissl bodies
- extensive RER
- mitochondria
- lipofuscin granules
- ligand gated channels and local potentials
14
Q
neuron cell body microtubules
A
called neurotubules
intermediate filaments = neurofilaments
15
Q
lipofuscin granules
A
- -formed from lysosomes
- -accumulate w/ age of neuron
16
Q
gray matter
A
cells bodies, dendrites and unmyelinated axons
17
Q
white matter
A
myelinated axons
18
Q
dendrites
A
- conduct local potentials
- contain organelles
- dendritic spines
- branching
- ligand gated channels
19
Q
axon hillock
A
origin of axon
no Nissl
associated w/ generation of ap (lowest resting potential)
20
Q
axon
A
- voltage gated channels
- conduct ap
- mito and microtubules
- telodendrites w/ synaptic vesicles
- presynaptic membrane
- can be myelinated
21
Q
classification of neurons due to function
A
- sensory or afferent
- motor or efferent
- interneurons
22
Q
afferent neurons
A
sensory
transmit sensory info from receptors to cns
23
Q
efferent neurons
A
motor
transmit motor info from cns to muscles/glands
24
Q
somatic motor neuron
A
innervate skeletal muscle
25
autonomic motor neurons
innervate glands, cardiac and smooth muscle
divided into para or sympathetic neurons
26
interneurons
transmit impulses within cns and between sensory and motor neurons
27
classifying neurons by number of processes
1. multipolar
2. bipolar
3. pseudounipolar
28
multipolar neurons
most common type
have a single axon and multiple dendrites
29
bipolar neurons
have 2 processes, one at each end of the spindle shaped neuron
associated w/ special senses such as smell and sight
30
pseudounipolar neurons
single process from the cell body that bifurcates into a central process
found in ganglia alongside spinal cord
31
classification of neurons by length of axon
1. golgi I
| 2. golgi II
32
golgi I neurons
neurons w/ long axons that leave the gray matter they are a part of
33
golgi II neurons
neurons w/ short axons which ramify thru the gray matter
34
bundle of axons in pns
nerve
35
bundle of axons in cns
tract
36
ganglion
aggregation of cell bodies and dendrites in pns
37
nucleus
aggregation of cell bodies and dendrites in cns
38
epineurium
a thick fibrous coat that covers an entire nerve
supplied by blood and lymphatic vessels
type I collagen and fibroblasts
39
perineurium
dense CT, covers bundles of axons within nerve
epithelial-like fibroblasts on inner surface
blood nerve barrier
40
perineurium fibroblasts
- -joined by tight junctions
- -zonula occludens
- -permeable barrier
- -this layer has to rejoined in surgery to reattach a limb
41
blood nerve barrier
endothelial cells of vessels are also linked by tight junctions
42
endoneurium
thin layer of reticular CT, surrounds individual fibers and schwann cells
type III collagen
43
channels on axon
K channels
| voltage gated Na and Ca channels
44
where are dense bodies found?
presynaptic membrane
45
anterograde direction
from cell body to distal end of axon
46
retrograde direction
from axon toward cell body
47
anterograde mvt
1. kinesin
2. can be slow, intermediate or fast
3. slow - 2 systems: SCa or SCb
48
SCa system
anterograde transport of preassembled microtubules and neurofilaments
49
SCb system
anterograde transport of enzymes, actin, clathrin
50
intermediate anterograde transport
50-100 mm per day
mitochondria and other membrane bound organelles
(slow is 1-6mm/day)
51
fast anterograde transport
utilizes microtubule motors
400 mm/day
synaptic vesicles and neurotransmitters
52
retrograde transport
1. dynein
2. carries endocytosed materials and recycled proteins
3. 100-300 mm/day
53
glial cells
non-neuronal cells
typically derived from embryonic neural crest tissue
support functions in pns and cns
54
glial cells are capable of ______ under appropriate conditions. ex. ?
cell division
```
astrocytes
oligodendrocytes
schwann cells
microglial cells
ependymal cells
```
55
astrocytes
- -neuroepithelium
- -only in cns
- -numerous processes that terminate on capillaries of pia matter
- -2 types
56
types of astrocytes
1. fibrous astrocytes
| 2. protoplasmic astrocytes
57
fibrous astrocytes
in white matter
long processes
few branches
58
protoplasmic astrocytes
in gray matter
short processes
many short branches
59
astrocyte functions
1. regulate composition of intercell matrix and entry into it
2. structural support
3. blood brain barrier
4. K sink
5. help form scar tissue in cns
60
astrocyte: blood brain barrier
--mediate exchange of nutrients and metabolites between blood and neurons
end feet form glia limitans
61
oligodendrocytes
1. neuroepithelium
| 2. only in cns
62
oligodendrocyte functions
1. lie close to neuron cell bodies in gray matter
2. function as satellite cells
3. surround unmyelinated axons in gray matter
4. myelinate axons in cns
63
_______ are the counterparts to schwann cells in the cns.
oligodendrocytes
64
schwann cells
1. from neural crest
2. myelinate axons in cns
each cell myelinates only a portion of a single axon
65
microglial cells
1. derived from bone marrow
2. phagocytic in cns
3. recruit leukocytes across bbb
4. monitor immune responses (with astrocytes)
66
ependymal cells
1. ciliated cuboidal cells
2. neuroepithelium
3. line ventricular system of cns
67
ependymal cell functions
function in transport
in choroid plexus - secrete cerebrospinal fluid
68
satellite cells
1. from neural crest
2. form moons around cell bodies in ganglia
3. function as insulators
69
myelination in pns
1. schwann cell plasmalemma wraps around axon
| 2. schwann cytoplasm is squeezed out leaving behind concentric layers of membranes
70
internal and external mesaxon
outer and innermost points of fusion between the outer leaflets
71
myelination in pns: intraperiod line
--electron dense line created by extracellular space between adjacent outer leaflets
72
major protein zero: intraperiod line
1. only in pns
| 2. creates homodimers
73
major protein homodimers
homodimers form homotetramers w/ opposing outer leaflets
74
in the cns, major protein zero is replaced by ?
a proteolipid protein
| w/ 4 homophobic domains
75
myelination in pns: major dense line
1. e- dense line
2. created by cytoplasmic space remnant between adjacent inner leaflets
3. myelin basic protein
76
myelin basic protein
1. found in pns
2. abundant protein associated w/ inner leaflets
3. stabilizes leaflet
77
Schmidt-lanterman clefts
(incisures)
| 1. residual areas of cytoplasm w/in major dense lines
78
if you have mutations in connexon 32?
you will be unable to myelinate axons
79
heterotypic tight junctions
found between the axolemma and the cytoplasmic loops adjacent to the node of ranvier
80
autotypic tight junctions
found between processes of adjacent schwann cells and the incisures of Schmidt-lanterman
81
presynaptic membrane
- -v gated Ca channels
- -SNAPs (proteins)
- -vesicle docking proteins
- -Synapsins
82
SNAPs
1. bind synaptic vesicles to the presynaptic membrane
2. soluble NSF
3. found in cytosol of terminal
83
vesicle docking proteins
SNAP receptors found in presynaptic and synaptic vesicular membranes
84
synapsins
filaments in presynaptic membrane
85
postsynaptic membrane has _______ receptors
neurotransmitter
86
list types of synapses - 6
1. axosomatic
2. axoaxonic
3. axodendritic
4. axospinous
5. excitatory
6. inhibitory
87
axosomatic
axon terminal synapse w/ neuron cell body
88
axoaxonic
axon terminal synapse w/ another axon
89
axodendritic
axon terminal synapse w/ a dendrite
90
axospinous
axon terminal synapse w/ a dendritic spine
91
excitatory synapse
more positive end-plate potential
closer to threshold
easier for the cell to fire
92
inhibitory synapse
more negative end-plate potential
farther from threshold
harder for the cell to fire
93
meninges and spaces: superficial to deep
```
bone
epidural space
dura mater
subdural space
leptomeninx
-arachnoid memb.
--arachnoid villi
---pia mater
```
94
the epidural space is ______ around the _____.
absent around brain
95
dura mater
1. tough thick dense fibrous CT
2. physical protection
3. serves as periosteum in cranium
96
around the spinal cord, the dura mater .…..
1. forms a CT tube that is separated from the bone of vertebrae by space (epidural space)
97
within the dura mater
1. endothelial lined venous sinuses
- -receive blood from cerebral drainage
- --cerebrospinal fluid via arachnoid villi
98
dural border cells
separate the dura mater from the subdural space
99
arachnoid
1. a meninx of delicate CT
2. outer layer faces subdural space
3. inner side attached to pia mater by delicate strands
100
outer layer of arachnoid
- -faces subdural space
| - -a single layer of arachnoid barrier cells
101
arachnoid trabeculae
delicate strands of CT connecting arachnoid and pia mater
102
subarachnoid space
space between arachnoid and pia mater
103
_______ fills the subarachnoid space
cerebrospinal fluid
104
arachnoid villi
1. make up arachnoid barrier cells
2. extend into venous sinuses of dura mater
3. allow passage of cerebrospinal fluid
105
pia mater
1. thin, delicate CT
2. lies directly on brain and spinal cord
3. follows contour of brain and dips into sulci
4. cannot be removed w/o damaging NT
106
pia mater CT is continuous w/
the perivascular CT of cerebral and spinal cord blood vessels
107
perivascular spaces
tunnels covered w/ pia mater
108
choroid plexus
1. a highly infolded simple cuboidal epithelium that extends into the ventricles from the roof plate
109
cerebrospinal fluid barrier
cuboidal cells of choroid plexus are linked by tight junctions forming the barrier
110
choroid plexus apical domain
apical microvilli
infolding basal memb.
have abundant mito to indicate active transport mechanisms
111
capillaries in choroid plexus
the endothelial cells lack tight junctions so they are very leaky
112
ependyma
1. layer of simple cuboidal epithelium - that lines the ventricular walls
2. cells linked by zonula adherens
3. have apical modifications
4. basal domain in contact w/ astrocytes
113
glia limitans
basal domains of ependymal cells are in contact w/ astrocytic processes forming the glia limitans
part of bbb
114
tanycytes in the 3rd ventricle are tightly linked …..
to adjacent ependymal cells
send processes thru glia limitans to form end-foot processes on underlying blood vessels
115
types of ganglia
sensory (dorsal root)
| autonomic
116
sensory ganglia
1. capsule of CT = epineurium
2. clustered w/ pseudounipolar neurons w/in capsule
3. postganglionic axons myelinated
117
autonomic ganglia
1. found in front of aorta
2. capsule of epineurium
3. clustered multipolar neurons
4. postganglionic axons not myelinated
118
autonomic ganglia neurons
- -cluster multipolar neurons
- -receive input from myelinated preganglionic neurons
*postganglionic axons are not myelinated
119
sensory ganglia satellite cells
1. similar to schwann
2. form single layer about cell bodies of neurons
3. apical surfaces face basal lamina not the neuron
120
autonomic ganglia satellite cells
1. similar to dorsal root ganglia but less numerous
