MSK - Histology - Nervous Tissue Flashcards
1
Q
True/False.
Neurons are both irritable (responsive to stimuli) and conductive.
A
True.
2
Q
The CNS is made up of what major portions?
A
Brain,
spinal cord
3
Q
What are the major portions of the brainstem?
A
Midbrain
pons,
medulla oblongata
4
Q
The peripheral nervous system is made of what major parts?
How many of each?
A
Cranial nerves (12);
spinal nerves (31)
5
Q
The brain is made up of what major portions?
A
Cerebrum,
cerebellum,
brainstem
6
Q
What is another term for neuronal cytoplasm?
What is another term for neuronal RER?
A
Perikaryon;
Nissl bodies
7
Q
Neurons typically have a maximum of how many dendrites?
Neurons typically have a maximum of how many axons?
A
15;
1
8
Q
Dendritic branches are called:
A
gemmules (spines)
9
Q
Axons originate at the:
What happens here?
A
Axon hillock;
summation (temporal and spatial)
10
Q
What basic neuron configuration (i.e. axonal and dendritic branching) do motor neurons have?
A
Multipolar
(multiple dendrites + 1 axon)
11
Q
What basic neuron configuration (i.e. axonal and dendritic branching) do general sensory neurons have?
A
Pseudounipolar
(sensory side + laterally removed soma + transmitting side)
12
Q
What basic neuron configuration (i.e. axonal and dendritic branching) do special sensory neurons have?
A
Bipolar
(sensory side and transmitting side bisected by soma)
13
Q
What neuron type is responsible for circuit formation and creating high neuronal interconnection?
A
Interneurons
(typically multipolar)
14
Q
Motor neurons are:
Sensory (general) neurons are:
Special sensory neurons are:
Interneurons are:
A
Multipolar;
pseudounipolar;
bipolar;
multipolar
15
Q
Bipolar neurons are:
Multipolar neurons are:
Pseudounipolar neurons are:
A
Special sensory;
motor (or interneurons);
sensory (general)
16
Q
Where is the most obvious location of a collection of pseudounipolar cell soma?
A
Any dorsal root ganglion
17
Q
True/False.
Interneurons are often multipolar.
A
True.
18
Q
Pyramidal cells and Purkinje cells receive large amounts of input from what type of neuron?
A
Interneurons
19
Q
What type of multipolar neuron is found primarily in the cerebrum?
What type of multipolar neuron is found primarily in the cerebellum?
A
Pyramidal cells;
Purkinje cells
20
Q
What type of cell is a pyramidal cell (e.g. multipolar, unipolar, bipolar, pseudounipolar, etc.)?
A
Multipolar
21
Q
What type of cell is a Purkinje cell (e.g. multipolar, unipolar, bipolar, pseudounipolar, etc.)?
A
Multipolar
22
Q
What basic neuron configuration (i.e. axonal and dendritic branching) do interneurons have?
A
Multipolar
23
Q
Where are pyramidal cells found?
A
The cerebrum
24
Q
Where are Purkinje cells found?
A
The cerebellum
25
In what layers of the cerebrum are pyramidal cells found?
With what functions are they associated?
Layers III and V;
memory, learning, sensory information integration, motor response initiation
26
The large motor neurons seen in the anterior horn are what kind of neuron?
What is found in abundance in their cytoplasm?
Multipolar;
Nissl bodies
27
What is the name of the extracellular space surrounding motor neurons found in the anterior horn?
What is found here?
Neuropile;
axons, dendrites, blood vessels, and glial cells
28
The lines coming from the right side of the image are indicating what structures?
What type of cell is this likely to be?
What is the extracellular space called?
Nissl bodies;
a motor neuron;
neuropile
29
What is the ratio of glial cells to neurons in the CNS?
10:1
30
What are the four glial cells of the CNS?
Astrocytes,
ependymal cells,
oligodendrocytes,
microglia
31
What shape are ependymal cells?
Columnar
32
What are the two main types of astrocyte?
Where does each (mainly) occur?
**Protoplasmic** (gray matter),
**fibrous** (white matter)
33
Glial tumors mostly arise from which type of astrocyte?
Fibrous astrocytes
34
What type of cell is shown in this micrograph?
Astrocytes
*(here shown under fluorescence)*
35
Astrocyte foot projections mostly wrap around what two structures?
Blood vessels (contributing to the BBB);
neurons (providing support, repair, and K+ / neurotransmitter removal)
36
What type of cell is shown in this micrograph?
A microglial cell
| (small, fibrous, dark-staining)
37
How many types of oligodendrocyte are there?
What are they?
3;
perivascular,
satellite,
interfascicular
38
What cells are stained 'G' and what cells are stained 'N' in this micrograph?
Glial cells;
neurons
39
What type of cell is shown in this micrograph?
Name the structure indicated by the 'P.'
Astrocytes;
foot processes
40
What are the main glial cells of the PNS?
Satellite cells;
Schwann cells
41
Peripheral nerve axon bundles are known as:
These bundles are surrounded by:
Fascicles;
connective tissue sheaths
42
What is the name for the connective tissue sheath surrounding each individual fascicle (bundle of axons)?
What is the name for the connective tissue sheath surrounding several fascicles (bundles of axons)?
Perineurium;
epineurium
43
A group of axons makes up a \_\_\_\_\_\_\_\_, a group of which makes up a \_\_\_\_\_\_\_\_.
Fascicle, nerve
44
What thin layer of connective tissue surround an individual axon and its associated Schwann cell?
Describe this connective tissue.
Endoneurium;
loose reticular fibers (type III collagen)
45
The permeability barrier of a nerve is made of what type of junctions?
This barrier is found in what layer of connective tissue?
Tight junctions;
perineurium
46
Describe the perineurium.
Flattened cells surround groups of axons that form fascicles
47
What type of tissue makes up the epineurium?
Dense irregular connective tissue
48
**True/False.**
One individual Schwann cell pairs with one individual axon at a particular point and wraps around it once.
False;
one Schwann cell wraps around one neuron many times at a particular point, making multiple layers of insulation
(from **a few** up to **150** layers from a single Schwann cell)
49
The length of axon that is covered by a Schwann cell is called the \_\_\_\_\_\_\_\_\_.
The short gaps of exposed axon between Schwann cells are called \_\_\_\_\_\_\_\_\_\_\_\_\_\_.
Internode (1 - 1.5 mm);
nodes of Ranvier
50
How long is the typical length of axon covered by a Schwann cell? What is this space called?
How many Schwann cells can be needed to myelinate a single axon?
1 - 1.5 mm, the internode;
100s
51
What type of myelinating cell is found in the PNS?
What *specific* type of myelinating cell is found in the CNS?
Schwann cells;
*interfascicular* oligodendrocytes
52
One Schwann cell can be attached to how many neurons?
One oligodendrocyte cell can be attached to how many neurons?
1;
up to 30
53
**True/False.**
Many PNS axons are not sheathed by Schwann cells and are not myelinated.
False;
although it is true that many are unmyelinated, all PNS axons are protected and supported ('sheathed') by Schwann cells
54
**True/False.**
A single oligodendrocyte can myelinate several internodes of the same axon.
True.
55
What term describes nervous conduction down myelinated axons from node of Ranvier to node of Ranvier?
Saltatory conduction
56
What is the purpose of nervous ganglia?
Sensory ganglia send information to the:
Autonomic (motor) ganglia send information to the:
To act as relay stations;
CNS;
effector organs
57
**True/False.**
Motor ganglia are synaptic stations.
**True/False.**
Sensory ganglia are synaptic stations.
True;
false
58
Which has its nucleus in a central position within the cell, a large multipolar neuron (e.g. a motor neuron) or a neuron found in a sensory ganglion?
Sensory ganglia neurons
(motor neurons have peripherally displaced nuclei as seen in this image)
59
What are the two major types of plexi (nets of ganglia) found in the enteric nervous system?
Submucosal (Meissner's);
myenteric (Auerbach's)
60
This micrograph shows nervous tissue between two separate layers of muscular tissue that have differing orientations.
This is most likely to be from what organ system?
What is this collection of nervous tissue called?
The gut;
the myenteric (Auerbach's) plexus
(of the enteric nervous system)
61
Name the type of synaptic junction:
an axon synapsing on a non-neuronal cell
Axosomatic synapse
62
Name the type of synaptic junction:
an axon synapsing on a dendritic spine
Axodendritic synapse
63
Name the type of synaptic junction:
an axon synapsing on an adjacent axon
Axoaxonic synapse
64
How long is the average synaptic cleft?
~25 nm
65
Presynaptic cholinergic neurons have what type of appearance to their vesicles?
Clear vesicles
66
Presynaptic adrenergic neurons have what type of appearance to their vesicles?
Dense vesicles
67
Which horns of the gray matter in spinal cord cross section will reach the outer surface of the cord?
What horns appear largest?
(Options: ventral, lateral, and dorsal horns)
Dorsal horns;
ventral horns
68
From superficial to deep, what are the three layers of cerebellar cortex in terms of type of neuron?
Molecular (synaptic);
Purkinje;
granular
69
What is the outer layer of the cerebellar cortex in terms of type of neuron?
Molecular (synaptic)
70
What is the middle layer of the cerebellar cortex in terms of type of neuron?
Purkinje (functional; motor)
71
What is the inner layer of the cerebellar cortex in terms of type of neuron?
Granular
| (small, densely packed neurons)
72
How many cellular layers of cerebral cortex are there?
From superficial to deep, what are the outer three cellular layers of the cerebral cortex?
6;
molecular (I),
external granular (II),
external pyramidal (III)
73
How many cellular layers of cerebral cortex are there?
From superficial to deep, what are the inner three cellular layers of the cerebral cortex?
6;
internal granular (IV),
internal pyramidal (ganglionic) (V),
multiform (polymorphic) (VI)
74
How many cellular layers of cerebral cortex are there?
From superficial to deep, what are they?
**6**;
molecular (I),
external granular (II),
external pyramidal (III),
internal granular (IV),
internal pyramidal (ganglionic) (V),
multiform (polymorphic) (VI)
75
What are the main functional cells of the cerebral cortex?
In what layers are they found?
Pyramidal cells;
layers III and V
76
What percent of interneurons are found in the CNS?
99.9%
77
Are any inclusions common in neurons?
Lipofuscin (especially in the elderly);
melanin (from the substantia nigra pars compacta)
78
For what types of movement is fast axonal transport used?
For what types of movement is slow axonal transport used?
Movement of vesicles and mitochondria;
cytoplasmic proteins for the assembly of microtubules and neurofilaments
79
What type of CNS cell is particularly small and not typically seen in normal brain tissues?
Microglia
80
**True/False.**
Ependymal cells can be either columnar or cuboidal.
True.
81
**True/False.**
Ependymal cells can have both cilia and microvili.
**True/False.**
If the above is true about either cilia or microvili, this means that the ependymal cells are epithelial cells.
True
(for movement or absorption purposes);
false
82
What shape is a Schwann cell nucleus?
Flat and small
83
What type of tissue is shown in this micrograph?
What are some of its defining characteristics?
Cardiac muscle;
striations, intercalated discs
84
What type of tissue is shown in this micrograph?
What are some of its defining characteristics?
Skeletal muscle;
striations
85
What type of tissue is shown in this micrograph?
What are some of its defining characteristics?
Smooth muscle;
non-striated
86
Which of these types of muscle is striated?
Cardiac
Smooth
Skeletal
Cardiac,
skeletal
87
88
Astrocytes
89
A. Autonomic ganglia
B. Smooth muscle
90
A. Myelinated nerve axon
B. Unmyelinated nerve axon
C. Schwann cell
D. Fibroblast
91
A. Purkinje cells
B. Molecular layer
C. Granular layer
92
A - F
A. Cerebellar tissue
B. Cortex
C. Medulla
D. Molecular layer
E. Granular layer
F. Purkinje cells
93
94
A. Dorsal root ganglion pseudounipolar cells
B. Satellite cells
95
96
Multipolar neuron
97
Myelin sheath
98
A. Cerebellar cortex
B. Pyramidal neurons
99
Nodes of Ranvier
100
101
*(Note: the synapse is just the tiny line. There is a synapse on either side of the central axon in the image)*
102
Autonomic ganglion
103
104
Peripheral nerves
105
Nervous tissue is composed of two major types of cells?
Neurons;
neuroglia (glial cells)
106
True/False. Unmyelinated peripheral neurons are often still enveloped in Schwann cell cytoplasm?
True.
(just not wrapped in multiple layers to create the myelination effect)
107
What type of cell is this and where is it likely to be found?
What are its cytoplasmic aggregates?
A motor (multipolar) neuron,
the ventral horn;
Nissl substance
108
Is Nissl substance basophilic or eosinphilic?
Why?
Basophilic;
high concentrations of rRNA
109
You identify a motor neuron in a section of spinal cord histology. Where did you find it?
In what parts of the neuron are you *not* likely to find Nissl substance?
The ventral horn;
the axon hillock and axon
110
What types of cell are most prominent in this slide?
What smaller cells surround these prominent cells?
Where is a likely location of the PNS where this slide was found?
Sensory neurons (pseudounipolar);
satellite cells;
dorsal root ganglion
111
This slide shows a portion of a sympathetic autonomic ganglion.
What inclusions are see in the cytoplasm?
Lipofuscin
| (in lysosomes)
112
**True/False.**
Dorsal root ganglia are synaptic locations.
**True/False.**
The ventral horns are synaptic locations.
**True/False**.
The dorsal horns are synaptic locations.
**True/False.**
Autonomic ganglia are synaptic locations.
False;
true;
true;
true
113
Name the three layers of connective tissue associated with nerves.
**Endoneurium** (surrounds each nerve fiber)
**Perineurium** (surrounds bundles of nerve fibers (i.e., fascicle))
**Epineurium** (dense irregular connective tissue that surrounds an entire nerve)
114
Endoneurium surrounds:
Perineurium surrounds:
Epineurium surrounds:
Each nerve fiber;
each bundle (fascicle) of nerve fibers;
an entire nerve
115
Why are longitudinally cut nerves "wavy" in appearance?
To allow stretching and movement with tissues
116
What type of connective tissue is epineurium?
Dense irregular connective tissue
117
What type of connective tissue fiber is associated with endoneurium?
Type III collagen
118
What type of connective tissue fiber is associated with epineurium?
Type I collagen (dense irregular connective tissue)
119
What type of connective tissue fiber is associated with Schwann cell basement membranes?
Type IV collagen
120
What type of connective tissue fiber is associated with Schwann cell basement membranes?
What type of connective tissue fiber is associated with endoneurium?
What type of connective tissue fiber is associated with epineurium?
Type IV collagen;
type III collagen;
type I collagen
121
Neurons releasing adrenergic products are characterized by what type of vesicle in their axons?
Dense (dark) vesicles
122
Neurons releasing cholinergic products are characterized by what type of vesicle in their axons?
Clear (light) vesicles
123
Which type of secretory axon is this more likely to be, cholinergic or adrenergic?
Cholinergic
| (clear vesicles)
124
Which type of secretory axon is this more likely to be, cholinergic or adrenergic?
Adrenergic
| (dense vesicles)
125
What are four primary types of motor neuron found in the body?
Where are their respective soma found?
Somatic motor neurons in the ventral horn;
autonomic motor neurons in the autonomic ganglia;
Purkinje cells in the cerebellum (between the granular and molecular layers);
\*pyramidal (Betz) cells in the cerebrum (layers III and V)
*(note: \*pyramidal cells are also responsible for cognition and many other tasks)*
126
What pyramidal (Betz) cell structure extends towards the superficial cerebral layers?
What pyramidal (Betz) cell structure extends towards the deep cerebral layers?
Apical dendrites;
the axon
127
Pyramidal (Betz) cells are characterized by ___________ extending superficially, ___________ extending laterally, and ___________ extending deeply.
apical dendrites,
basal dendrites,
axons
128
How does the rabies virus get to the host CNS from the original wound (often a peripheral bite mark)?
How does the rabies virus get to the host salivary glands from the CNS?
It rides dyneins back to the CNS;
it rides kinesins back to the salivary glands
129
How does the rabies virus get to the host CNS from the original wound (often a peripheral bite mark)?
It rides dyneins in the peripheral nerves
130
How does the rabies virus get to the host salivary glands from the CNS?
It rides kinesin proteins down microtubules in the peripheral nerves
131
What explains the extremely high latency period between a person being bitten by a rabid animal and that same person showing signs/symptoms of the disease?
(sometimes years)
The rabies virus rides dyneins back to the CNS and then kinesins down to the salivary glands from there
*(this can be an extremely long process, especially if the initial rabid bite was far in the periphery (e.g. the hand or foot) and a small, slow nerve was infected)*
