Neurons Flashcards
(162 cards)
1
Q
Constitute the genetic, anatomic, trophic, and
functional units of the nervous system
A
Neurons
2
Q
Have the capacity to receive impulses from receptor
organs or other neurons
A
Neurons
3
Q
Have lost the capacity to undergo cell division
A
Neurons
4
Q
Have the capacity to transmit impulses to other neurons or effector organs
A
Neurons
5
Q
Consist of the cell body and its processes, dendrites, and a single axon
A
Neurons
6
Q
the name given to the nerve cell and all its
processes
A
Neuron
7
Q
excitable cells that are specialized for the
reception of stimuli and the conduction of the nerve impulse
A
neurons
8
Q
Single neurite divides
a short distance from
cell body
A
Unipolar
9
Q
Many dendrites and
one long axon
A
Multipolar
10
Q
Single neurite
emerges from either
end of cell body
A
Bipolar
11
Q
Single long axon
A
Golgi type I
12
Q
Short axon that are
with dendrites resembling a star-
shape appearance
A
Golgi type II
13
Q
Location of Unipolar
A
Posterior root
ganglion
14
Q
Location of Bipolar
A
Retina, sensory
cochlea, and
vestibular ganglia
15
Q
Location of multipolar
A
Fiber tracts of brain
and spinal cord,
peripheral nerves, and
motor cells of spinal
cord
16
Q
Location of Golgi Type I
A
Fiber tracts of brain
and spinal cord,
peripheral nerves, and
motor cells of spinal
cord
17
Q
Location of Golgi Type II
A
Cerebral and
cerebellar cortex
18
Q
Also called the soma or perikaryon
A
NERVE CELL BODY
19
Q
Contains the organelles found in other cells, including a large nucleus and a prominent nucleolus
A
NERVE CELL BODY
20
Q
Has receptor molecules on its plasmalemmal surface that confer sensitivity to various neurotransmitters
A
NERVE CELL BODY
21
Q
Is characteristic of nerve cells and consists of
rossettes of polysomes and rough endoplasmic reticulum
A
NISSL SUBSTANCE
22
Q
Plays role in protein synthesis
A
NISSL SUBSTANCE
23
Q
Is abundant throughout the cytoplasm and dendrites but is not found in the axon hillock or in the axon
A
NISSL SUBSTANCE
24
Q
Are membrane-bound dense bodies that contain
hydrolytic enzymes and are involved in the process of
intracellular digestion
A
LYSOSOMES
25
Removes metabolized substances in the
neuron
LYSOSOMES
26
A genetic defect in the synthesis of lysosomal enzyme
results in a storage disease
(Tay-Sachs disease [GM2
gangliosidosis])
27
Lysosomes exist in 3 forms
Primary lysosomes: which have just been
formed
o Secondary lysosomes: which contain
partially digested material
▪ Eventually will be needed to
remove from the neuron
o Residual bodies: in which the enzymes are
inactive and the bodies have evolved from
digestible materials
28
Form an internal supportive network, the
cytoskeleton
FILAMEONTOUS PROTEN STRUCTURES
29
Largest among the filamentous protein structures found in the neuron
Microtubules (25nm in diameter)
30
Are found in the cell body, dendrites and axons
Microtubules (25nm in diameter)
31
Crucial in the development and maintenance of cell shape
Microtubules (25nm in diameter)
32
Responsible for the intracellular transport of peptide vesicles and organelles
Microtubules (25nm in diameter)
33
Second largest among the filamentous protein
structures
Neurofilaments (10nm in diameter)
34
Consists of spiral protein threads that play a role in
developing and regenerating nerve fibers
Neurofilaments (10nm in diameter)
35
Degenerate in Alzheimer’s disease to form
neurofibrillary tangles
Neurofilaments (10nm in diameter)
36
Are composed of actin
Microfilaments (5nm in diameter)
37
Facilitate movement of plasma membrane and
growth of nerve cell processes
Microfilaments (5nm in diameter)
38
Pigmented inclusions of cytoplasm that accumulate with aging
Lipofuscin (lipochrome granules)
39
considered residual bodies derived from
lysosomes
Lipofuscin (lipochrome granules)
40
A blackish pigment in the neurons of the substancia nigra and locus ceruleus
Neuromelanin (melanin)
41
Disappears from the substancia nigra and the locus ceruleus in Parkinson’s disease
Neuromelanin (melanin)
42
Are eosinophilic intracytoplasmic inclusion bodies
found in the substancia nigra in patients with
Parkinson’s disease
Lewy bodies
43
Are intracytoplasmic inclusion bodies found in the
hippocampus in patients with Alzheimer’s disease
Hirano bodies
44
Are intracytoplasmic inclusion bodies found in people
with rabies
Negri and lyssa bodies
45
Are processes that extend from the cell body
DENDRITES
46
Contain cytoplasm similar in composition to that of
the cell body, however no Golgi apparatus is present
DENDRITES
47
Conduct in a decremental fashion but may be capable
of generating action potentials
DENDRITES
48
Receive synaptic input and and transmit it toward the
cell body
DENDRITES
49
Arise from either the cell body or a dendrite
AXONS
50
Originate from the axon hillock (devoid of Nissl
substance)
AXONS
51
Give rise to the collateral branches
AXONS
52
May be myelinated or unmyelinated
AXONS
53
Generate, propagate, and transmit action potential
AXONS
54
End distally in terminal boutons in synapses with neurons, muscle cells, and glands
AXONS
55
Consists of axons and their glial investments
NERVE FIBERS
56
Are classified by function, fiber size, and conduction velocity
NERVE FIBERS
57
Is the name given to an axon (or dendrite) of a nerve
cell
NERVE FIBERS
58
Bundles of nerve fibers found in the central nervous
system are often referred to
nerve tracts
59
Bundles of nerve fibers found in the peripheral
nervous system are called
peripheral nerves
60
Diameter
Ia (Aα)
12-20
61
Diameter
IB (Aα)
12-20
62
Diameter
II (Aβ)
5-12
63
Diameter
III (Aδ)
2-5
64
Diameter
IV (C)
0.5-1
65
Diameter
Alpha (Aα)
12-20
66
Diameter
Gamma (Aγ)
2-10
67
Diameter
Preganglionic
autonomic
fibers (B)
<3
68
Diameter
Postganglionic autonomic
fibers (C)
1
69
CV
Ia (Aα)
70-120
70
CV
IB (Aα)
70-120
71
CV
II (Aβ)
30-70
72
CV
III (Aδ)
12-30
73
CV
IV (C)
0.5-2
74
CV
Alpha (Aα)
15-120
75
CV
Gamma (Aγ)
10-45
76
CV
Preganglionic
autonomic
fibers (B)
3-15
77
CV
Postganglioni
c autonomic
fibers (C)
2
78
Proprioception, muscle
spindles
Ia (Aα)
79
Proprioception, golgi tendon
organs
IB (Aα)
80
Touch, pressure, and
vibration
II (Aβ)
81
Touch, pressure, fast pain,
and temperature
III (Aδ)
82
Slow pain and temperature,
unmyelinated fibers
IV (C)
83
Alpha motor neurons of
ventral horn
Alpha (Aα)
84
Gamma motor neurons of
ventral horn
Gamma (Aγ)
85
Myelinated preganglionic
autonomic fibers
Preganglionic
autonomic
fibers (B)
86
Unmyelinated
postganglionic autonomic
fibers
Postganglioni
c autonomic
fibers (C)
87
Sometimes referred to as the insulator of the nerve
fiber; responsible for conducting the appropriate
nerve impulses to the different areas of the body
MYELIN SHEATH
88
Transmission of nerve impulses is amplified
by the myelin because it uses
saltatory
conduction
Current jumps from one node of Ranvier to
the other
89
Myelin sheath Is produced in the PNS by
Schwann cells
90
Myelin Sheath Is produced in the CNS by
by oligodendrocytes
91
Myelin sheath Is interrupted by the
the node of Ranvier
92
Consists of a spirally wrapped plasma membrane
MYELIN SHEATH
93
The smaller axons of the central nervous system, the
postganglionic axons of the autonomic part of the
nervous system, and some fine sensory axons
associated with the reception of pain are
nonmyelinated
94
In the peripheral nervous system, each axon which is
usually less than 1 nm in diameter, indents the
surface of the Schwann cell so that it lines within a
trough
95
In the central nervous system, nonmyelinated nerve
fibers run in small groups and are not particularly
related to the
oligodendrocytes
96
Are the sites of functional contact of a nerve cell with
another nerve cell, an effector cell, or a sensory
receptor cell
SYNAPSES
97
Consists presynaptic membrane, synaptic cleft, and
postsynaptic membrane
SYNAPSES
98
axons communicating with
dendrites of another neuron
Axodendritic:
99
axon communicating directly
with nerve cell body of another neuron
Axosomatic:
100
axon directly communicating to
the axon of another neuron
Axoaxonic:
101
dendrites communicating
to dendrites of another nerve cell body
Dendrodendritic:
102
Arise non-neuronal cells of the PNS and the CNS
NEUROGLIA
103
Neuroglia Abundant in the __
CNS
104
Neurons are __, while neuroglia
serve to __
Functional, support
105
Neuroglia arise from
the neural tube and neural crest
106
capable of miotic cell division throughout adult
life
NEUROGLIA
107
best revealed by gold and silver impregnation
stains
NEUROGLIA
108
Neuroglia classification
Macroglia (astrocytes and oligodendrocytes)
Microglia
Ependyma
109
Are the largest glial cells
ASTROCYTES
110
Consist of fibrous astrocytes, which are found mainly
in white matter, and protoplasmic astrocytes which
are found mainly in gray matter
ASTROCYTES
111
Play a role in the metabolism of certain
neurotransmitters (GABA, serotonin, glutamate)
ASTROCYTES
112
Buffer the potassium concentration of the
extracellular space
ASTROCYTES
113
Contain glial filaments and glycogen granules as their
most characteristic cytoplasmic components
ASTROCYTES
114
In damaged areas of the brain, form glial scars, a
condition called
gliosis
115
Are the processes that form the external glial limiting
membrane and the internal glial limiting membrane
ASTROCYTIC END FEET
116
surrounds capillaries
Perivascular end feet:
117
surrounds neurons
Perineural end feet:
118
marker
for astrocytes
glial fibrillary acidic protein (GFAP)
119
Like lipofuscin granules
Residual bodies of the astrocytes
GLYCOGEN GRANULES
120
Small glial cells with few short processes
OLIGODENDROCYTES
121
Lack glial filaments and glycogen granules
OLIGODENDROCYTES
122
myelin-forming cells of the CNS; one
oligodendrocyte can myelinate numerous (up to 30)
axons
OLIGODENDROCYTES
123
Do not have glycogen granules and glial filaments
o Present in astrocytes
Do not have glycogen granules and glial filaments
o Present in astrocytes
124
Oligodendrocyte consist of
o Interfascicular oligodendrocytes: found in
white matter
o Satellite cells: found in gray matter
125
Arise from monocytes, which enter the CNS via
abnormal blood vessels
MICROGLIA (HORTEGA CELLS)
126
Are activated by inflammatory and degenerative
processes
MICROGLIA (HORTEGA CELLS)
127
Are macrophages, which are migratory and
phagocytize debris of nerve tissue
o Garbage collectors among the neuroglial
cells
MICROGLIA (HORTEGA CELLS)
128
Line the central canal of the spinal cord and ventricles of the brain
EPENDYMAL CELLS
129
Possess cilia only in embryologic stages in man that
originate from blepharoplasts (basal bodies), which
can be stained by phosphotungstic acid-hamatoxylin
(PTAH)
EPENDYMAL CELLS
130
Include choroid epithelial cells of the choroid plexus
and tanycytes of the third ventricles; the choroid
plexus cells produce CSF and are interconnected by
tight junctions that constitute the blood-CSF barrier
EPENDYMAL CELLS
131
Are derivatives of the neural crest
SCHWANN CELLS (NEUROLEMMAL CELLS)
132
Are myelin-forming cells of the PNS; a Schwann cell
myelinates only one internode (only one peripheral
axon)
SCHWANN CELLS (NEUROLEMMAL CELLS)
133
Invest all unmyelinated axons of the PNS
SCHWANN CELLS (NEUROLEMMAL CELLS)
134
Function in regeneration and remyelination of
severed axons in the PNS
SCHWANN CELLS (NEUROLEMMAL CELLS)
135
Are separated from each other by the node of Ranvier
SCHWANN CELLS (NEUROLEMMAL CELLS)
136
Majority of the tumors in the nervous system (CNS) are arising from
neuroglial cells
137
Gliomas Are derived from the 3 glial cells:
astrocytes,oligodendrocytes, and ependymocytes
138
Result from proliferation of glioblasts, embryonic precursors
TUMORS OF THE NEUROGLIAL CELLS (GLIOMAS)
139
Represent 50% of primary intracranial tumors
TUMORS OF THE NEUROGLIAL CELLS (GLIOMAS)
140
Benign astrocytomas
Astrocytomas
141
Malignant astrocytomas (GBM)
Gliobastomamultiforme (most
malignant)
142
Developed in vestibulocochlear nerve
Schwanommas
143
Occurs toward the proximal end of an axon, including the cell body
RETROGRADE DEGENERATION
144
Reaction begins__ days or sooner after injury and
reaches a maximum in about __ days
RETROGRADE DEGENERATION
2, 20
145
RETROGRADE DEGENERATION Involve
o Disappearance of Nissl substance
(chromatolysis)
o Swelling of the cell body
o Flattening and displacement of the nucleus
from central location to the periphery
146
Occurs toward the distal end of the axon
* Takes place in both the PNS and the CNS
ANTEROGRADE (WALLERIAN) DEGENERATION
147
Characterized by successive fragmentation and
disappearance of axons and myelin sheaths and by
secondary proliferation of Schwann cells
ANTEROGRADE (WALLERIAN) DEGENERATION
148
Nerve supply towards the skeletal muscles will be
affected and may cause atrophy in the long term
ANTEROGRADE (WALLERIAN) DEGENERATION
149
A myelinated peripheral nerve fiber consists of an
axon, a myelin sheath and its basement membrane,
and a delicate connective sheath, the endoneurium
The severed distal nerve fiber maintains its integrity
and provides a tube of basement membrane and
endoneurium into which an axon sprout grows
REGENERATION OF THE PERIPHERAL NERVE FIBER
150
Schwann cells proliferate along a degenerating axon
and myelinate a new axon sprout, which grows at the
rate of
3 mm/day
151
If the path of regenerating axons is blocked, a
traumatic neuroma forms at the
site of obstruction
(amputation neuroma)
152
No basement membranes or endoneurial
investments surround axons of the CNS
REGENRATION OF AXONS IN THE CNS
Effective regeneration does not occur in the CNS
153
Interruption of certain CNS pathways results in
degeneration of denervated elements
TRANSSYNAPTIC (TRANSNEURONAL) DEGENERATION
154
Responsible for transporting all newly synthesized
membranous organelles (vesicles) and precursors of
neurotransmitters at the rate of
FAST ANTEROGRADE TRANSPORT
200-400 mm/day
155
FAST ANTEROGRADE TRANSPORT
mediated by
microtubules and kinesin (fast transport
is microtubule dependent)
156
* Facilitates the transport of mitochondria
* Occurs at the rate of
50 - 100 mm/day
FAST MITOCHONDRIA TRANSPORT
157
Is responsible for transporting cytoskeletal and cytoplasmic elements at the rate of
SLOW ANTEROGRADE TRANSPORT
1-5 mm/day
158
from cell body towards the
axon down to its terminal ends
Anterograde:
159
Transports neurofilaments and microtubules
SLOW ANTEROGRADE TRANSPORT
160
FAST RETROGRADE TRANSPORT
Returns used materials from the axon terminal to the
cell body for degradation and recycling at the rate of
100-200 mm/day
161
Transport nerve growth factor and neurotropic
viruses and toxins
FAST RETROGRADE TRANSPORT
162
FAST RETROGRADE TRANSPORT
is mediated
by microtubules and dynein
