Nervous tissue Flashcards
(108 cards)
1
Q
Neuroglia
A
Supporting cells for neurons
2
Q
CNS is derived from the ___.
A
Neural tube
3
Q
CNS components
A
Brain and spinal cord
4
Q
Each neuron is identical. T/F
A
False, they are all unique
5
Q
Adult neurons are ___>
A
Post-mitotic
6
Q
Neurons comprise the smallest and largest cells of the body. T/F
A
True
7
Q
Morphological classification of neurons
A
Multipolar
Bipolar
Unipolar / pseudopolar
8
Q
What is the most common type of morphological neuron?
A
Multipolar (motor and interneurons)
9
Q
What morphological neuron is associated with receptors for special sense?
A
Bipolar neurons
10
Q
Where are unipolar / pseudopolar neurons located?
A
Sensory neurons in spinal and cranial ganglia
11
Q
Functional classification of neurons
A
Sensory
Interneurons
Motor
12
Q
What is the dominant organelle in the cell body of neurons?
A
Rough endoplasmic reticulum
13
Q
What is the dominant organization of DNA in the nucleus of neurons?
A
Euchromatin
14
Q
What are the prominent organelles in the cell body of neurons?
A
rER, Golgi, many mitochondria, Nissl bodies, neurofilaments and microtubules, lipofuscin granules
15
Q
Cell bodies are also referred to as ___ or ___.
A
Perikaryon, soma
16
Q
Nissl bodies
A
Basophilic ribosomes and rER
17
Q
Proximal vs. distal characteristics of dendrites
A
Proximal: same as perikaryon
Distal: No Golgi, less Nissl bodies, more MTs
18
Q
Dendritic spines
A
Small extensions of dendrites that increase receptor surface area
19
Q
Axoplasm characterisitcs
A
Abundant cytoskeleton (neurofilaments / MTs), no ribosomes / rER (Nissl)
20
Q
Neurofibrils
A
Clusters of neurofilaments and microtubules
21
Q
___ transmit stimuli towards the soma.
A
Dendrites
22
Q
Dendrites have a uniform diameter. T/F
A
False, they are tapered
23
Q
Does the axon hillock contain organelles?
A
No
No Nissl
24
Q
Where is the AP generated?
A
The initial segment of the axon
25
The axoplasm is limited by the ___.
Axolemma
26
Axon characterisitcs
Mitochondria
No Golgi / rER / ribosomes
Lots of neurofilaments and microtubules
27
___ have rough surfaces (spines) while ___ have smooth surfaces.
Dendrites, axons
28
Are dendrites myelinated?
No
29
___ mediates anterograde transport.
Kinesin
30
___ mediates retrograde transport.
Dynein
31
Retrograde transport goes from ___ and ___ to ___.
Axon terminals, dendrites, perikaryon
32
Anterograde transport
Carries material from perikaryon to periphery
| By kinesin
33
Scwann cells are part of the ___ nervous system.
Peripheral
34
Satellite cells are part of the ___ nervous system.
Peripheral
35
Astrocytes are part of the ___ nervous system.
Central
36
Oligodendrocytes are part of the ___ nervous system.
Central
37
Microglia are part of the ___ nervous system.
Central
38
Ependymal cells are part of the ___ nervous system.
Central
39
Schwann cells
Form myelin around axons
PNS
One myelin sheath per cell
40
Myelin sheath are 80% ___ and ___ and 20% ___.
Lipid, cholesterol
| Protein
41
Internodes
Myelin sheath between nodes of ranvier
42
Saltatory conduction
AP jumps from node to node
43
Type A fibers
Thick, myelinated, long internodal regions, highest velocity
- -Alpha: proprioception, somatic motor
- -Beta: Touch, pressure
- -Gamma: Motor to spindle
- -Delta: pain, cold, touch
44
Type B fibers
Thinner myelin and smaller diameter than A fibers, moderate velocity
45
Type C fibers
Thinnest, lack myelin, slowest velocity
46
Satellite cells
Surround neurons in PNS ganglia, provide electrical insulation and exchange
47
Satellite cells in the ___ function to provide ___ and ___.
PNS, electrical insulation, metabolic exchange
48
Neurons are more prevalent than neuroglial cells. T/F
False, 10:1 neuroglia to neurons
49
What are the 4 types of neuroglial cells in CNS?
Astrocytes, oligodendrocytes, microglia, ependymal cells
50
Oligodendrocytes
Produce CNS myelin to insulate / protect axons
| Provides multiple myelin sheaths
51
Both Schwann cells and oligodendrytes produce multiple myelin sheaths per cell. T/F
False, one schwann cell produces one myelin sheath
52
Microglia
Smallest neuroglia, proliferate and become phagocytic in CNS injury / disease
53
What is the smallest neuroglia?
Microglia
54
Ependymal cells
Line ventricles and central canal of spinal cord, ciliated to move CSF
55
The choroid plexus is composed of specialized ___.
Ependymal cells
56
What are structural features of ependymal cells?
- -Cuboidal / columnar
- -Have cilia / microvilli
- -Small, basally located nucleus
57
Groups of neuronal bodies in the PNS are called ___.
Ganglia
58
Bundle of nerve fibers in the CNS are called?
Tract
59
Astrocyte
Largest neuroglia, proliferate in injury/disease
| Functions: form BBB, support, buffering potassium, NTs, synapse formation/efficiency
60
Gray matter
Neuronal cell bodies, many unmyelinated fibers, and glia
61
White matter
Myelinated fibers and glial cells
62
Cerebral cortex
Thin layer of grey matter on the surface of the cerebral hemispheres
63
In the spinal cord, the gray matter inside contains ___ and ___.
Ventral motor neurons and interneurons
64
In the spinal cord, the white matter inside contains ___.
Myelinated fibers
65
In the brain, the white matter is located ___ and the grey matter is located ___.
In center
| At periphery
66
In the spinal cord, the white matter is located ___ and the grey matter is located ___.
Outside
| Center (H)
67
What are the functions of the cerebral cortex?
- -Initiation of motor responses
- -Integration of sensory signals
- -Consolidation of info into memories
68
The central canal of the spinal cord is a continuation of the ___ of brain and is lined with ___.
Ventricles
| Ependymal cells
69
The dorsal horns of the spinal cord receive ___ info from ___ axons.
Sensory
70
The ventral horns of the spinal cord contain the ___ neurons that send ___ axons to the ventral roots.
Motor
71
The ___ horns receive sensory input while the ___ horns send motor output.
Dorsal
| Ventral
72
Ganglion
Collections of neuronal cell bodies outside of the CNS
73
The sensory axons include ___ sensory neurons and ___ sensory neurons.
Visceral (autonomic)
| Somatic
74
The motor axons include ___ motor neurons and ___ motor neurons.
Visceral (autonomic)
| Somatic
75
Autonomic ganglia
Motor ganglia where pre/post-ganglionic neurons of ANS synapse (SNS / PSNS ganglia)
Multi-polar cell bodies surrounded by satellite cells
Regulate gland secretion and smooth/cardiac muscle
76
Where are the autonomic ganglia located?
Near / in organs they innervate
77
Autonomic ganglia are have ___ cell bodies surrounded by ___ cells.
Multipolar
| Satellite
78
Sensory (craniospinal) ganglia
Sensory ganglia of cranial nerves and dorsal roots of spinal nerves (no synapse in ganglia)
Round, pseudounipolar cell bodies
79
___ ganglia have neuronal clusters while ___ ganglia do not.
Sensory
| Autonomic
80
___ ganglia have synapses while ___ do not.
Autonomic
| Sensory
81
Autonomic ganglia have ___ structure with ___ nucleus while sensory ganglia have ___ structure with ___ nucleus.
Multipolar, eccentric
| Pseudopolar, central
82
Nerves can either sensory or motor, not both. T/F
False
83
Epineurium
AKA fascia
Covers nerves
Dense irregular CT
84
Connective tissue layers are all formed by ___.
Fibroblasts
85
Perineurium
Covers each bundle of nerve fibers, divides nerves into fascicles
Inner squamous cells connected by tight junctions, preventing passive movement of macromolecules (blood-nerve barrier)
Irregular CT
86
___ covers bundles of nerve fibers, separating them into ___.
Perineurium, fascicles
87
Endoneurium
Thin layer of reticular fibers that surrounds individual fibers
88
The epineurium is made of ___.
The perineurium is made of ___.
The endoneurium is made of ___.
Dense, irregular CT
Irregular CT
Reticular fibers
89
The perineurium contains ____ on the inner surface. What function does this have?
Tight junctions prevent macromolecule passage, form blood-nerve barrier
90
The most common type of nerves are sensory, motor, or mixed?
Mixed, with both afferent and efferent fibers
91
In the CNS, the death of neurons is followed by what?
Proliferation of neuroglia (ex: astrocytosis)
92
Axons and myelin degenerate ___ in the PNS after axonal transection.
Distally
93
Wallerian degeneration
Anterograde
| Axons and myelin degenerating distally
94
What cleans away debris in degeneration of PNS axons?
Schwann cells and macrophages
95
Chromatolysis
Dissolution of Nissl substance due to transection of axons
96
The transection of axons leads to the death of neurons. T/F
False
97
Nerve degeneration and regeneration in PNS
1. Axons and myelin distal to lesion degenerate (cleared by macrophages)
2. Schwann cells divide and form endoneurial tube/column attached to effector organ
3. Axonal stump produces sprouts that enter endoneurial Schwann tube
98
Axonal regeneration in PNS rate is?
2-3 mm/day
99
Functional regeneration of axons in the CNS occurs slower than in the PNS. T/F
False, it does not occur
100
Nerve degeneration and regeneration in CNS
1. Axons / myelin degenerate (Wallerian), oligodendrocytes die
2. Microglia can't remove debris (inhibits axonal growth)
3. Astrocytes proliferation / hypertrophy, form glial scars which inhibit axonal regeneration
101
Histological features of sensory neurons mediating pain as compared with touch.
Touch (type A beta fibers) are larger and have higher velocity than pain neurons (Type C thin, unmyelinated fibers)
102
What neuronal microstructure is associated with old age?
Lipofuscin granules (remnants from lysosomes)
103
What is the largest neuroglial cell type?
Astrocytes
104
Which neuroglial cell type forms a glial scar? Where?
Astrocytes in CNS
105
The phagocytic neuroglia cells in the CNS are?
Microglia
106
Sensory neurons morphology
Pseudounipolar
| Central nucleus, neuronal clusters, no synapses, satellite cells, prominent nucleolus
107
Which membrane has a greater density in neuronal synapse: presynaptic or postsynaptic?
Postsynaptic
108
Autonomic neurons morphology
Mulitpolar, eccentric nucleus, not clustered, synapses
