NEUROCYTOLOGY Flashcards
(124 cards)
1
Q
Neurons and Glial cells derived from the ___________.
A
Neuroectoderm
2
Q
Supporting structures of the nervous system derived from the __________.
A
Mesoderm
3
Q
The functional unit of the nervous system
A
Neurons
4
Q
TRUE/FALSE
Signaling and Trophism are the most important function of the neurons?
A
TRUE
Other functions:
1. Generates and conducts electrical activity
- Transmits information throughout the N.S.
- Exerts long-term effects required for storage of information
5
Q
TRUE/FALSE
Normal mature neurons do not proliferate, but they can undergo adaptive changes in response to injury?
A
TRUE
6
Q
These supporting cells of Neuroectodermal origin comes from the greek word which means “glue”
A
Glial cells
7
Q
This cells mainly glue together or support the neurons to make-up the nervous system
A
Glial cells
8
Q
Consists of multiple tightly wrapped layers of plasma membrane that ensheathe large diameter axons.
A
Myelin
9
Q
Form myelin sheaths in CNS (spinal cord and brain)
A
Oligodendrocytes
-In the CNS, processes from a SINGLE oligodendrocyte contribute to the myelin sheath of SEVERAL axons near the cell (1: many)
10
Q
Form myelin sheaths in PNS (peripheral nerves and cranial nerves)
A
Schwann cells
-each Schwann cells interact w/ one axon (1:1) and contributes to the formation of a single internode.
11
Q
star-like glial cells of the CNS
A
Astrocytes
12
Q
Lie near both neurons and blood vessels
A
Astrocytes
13
Q
maintains homeostasis and chemical microenvironment of the brain and spinal cord
A
Astrocytes
14
Q
provide SELECTIVE BARRIER between the ventricular fluid and the brain substance
A
Ependymal cells
15
Q
TRUE/FALSE
Ependymal cells form a single layer of ciliated cuboidal epithelial cells that lines the entire ventricular system
A
FALSE
Ependymal cells form a SINGLE layer of CILIATED COLUMNAR epithelial cells that lines the entire ventricular system
16
Q
What are the 4 supporting cells in neuroectodermal in origin?
A
4 supporting cells in neuroectodermal in origin
- oligodendrocytes
- Schwann cells
- astrocytes
- ependymal cells
17
Q
TRUE/FALSE
Microglia and Connective tissue cells are supporting cells of ectoderm origin?
A
FALSE
Microglia and Connective tissue cells are supporting cells of MESODERM origin
18
Q
They are mesodermal cells of monocyte lineage that migrate into the CNS along with blood vessels from the mesoderm surrounding the neural tube.
A
Microglia
Remember M=M=M!
Mesoderm= Monocyte= microglia
19
Q
They are mesodermal cells that are normally present in small numbers in the brain and spinal cord and only proliferate in response to injury
A
Microglia
They are mesodermal cells that are normally present in small numbers (physiologic state) and migrate in the CNS, proliferate to become scavenger cells/specialized macrophages, removing damaged tissues (pathologic state)
20
Q
Meninges surrounding the CNS
A
Connective tissue cells:
Dura, pia and arachnoid
21
Q
Fibrous connective tissue surrounding the PNS
A
Epineurium, Perineurium and Endoneurium
22
Q
They are collectively known as leptomeninges
A
Pia and Arachnoid
23
Q
also known as Pachymeninx
A
Dura mater
24
Q
it gives rise to the choroid plexus which produces CSF
A
Ependymal cells
25
Transient neurologic disorders that may primarily affect neuronal function alone (WITHOUT changes in the physical appearance of the cell)
Transient neurological disorders:
- seizures
- TIA (transient ischemic attacks) aka mild stroke
- hypokalemic paralysis
26
TRUE/FALSE
Oxidative metabolism of glucose in the mitochondria is vital for cell survival in the N.S.
TRUE
Oxidative metabolism of glucose in the mitochondria is vital for cell survival in the N.S.
Both Oxygen and Glucose supply is needed
27
Most ATP consumptions of the nervous system is for fueling what?
NA-K ATPase pump
-to restore the ion gradient altered by excitatory neurotransmission and neuronal activity
28
Critical for preventing excessive accumulation of glutamate (synaptic space) and calcium ions (in the cytosol), both of which are toxic to cells
ATP
Critical for preventing excessive accumulation of glutamate (synaptic space) and calcium ions (in the cytosol), both of which are toxic to cells
29
NECROSIS/APOPTOSIS
abrupt ATP depletion
Necrosis
abrupt ATP depletion- hypoxia, hypoglycemia, and ischemia
30
NECROSIS/APOPTOSIS
slower ATP depletion
Apoptosis
31
The acute depletion of ATP leads to neuronal damage from excessive accumulation of _______.
L-glutamate
32
NECROSIS/APOPTOSIS
This process is called Excitotoxicity
Necrosis
33
NECROSIS/APOPTOSIS
Excessive mechanical strain
Necrosis
Excessive mechanical strain- traumatic injury
34
NECROSIS/APOPTOSIS
excessive neuronal energy demands
Necrosis
excessive neuronal energy demands- Status Epilepticus
35
A form of programmed cell death that is essential for normal development and tissue homeostasis
Apoptosis
36
3 Important triggers of Apoptosis.
3 Important triggers of Apoptosis:
1. DNA mutations
2. Inflammatory mediators
3. Abnormal accumulation of intracellular proteins, and oxidative stress
37
Homeostatic process by which cells degrade its organelles to maintain balance between synthesis, degradation, and subsequent turnover
Autophagy
38
3 specific pathologic reactions of neurons
ISCHEMIC CELL CHANGE
CENTRAL CHROMATOLYSIS
NEURONAL INCLUSIONS
39
It is a specific pathologic reaction that is due to deprivation of oxygen and cessation of oxidative metabolism
Ischemic cell change
40
A change in neuronal cell bodies after severe injury to the axons.
Central Chromatolysis
41
Also called as axonal reaction
Central Chromatolysis
42
Occurs in the distal part of axon when the parent body is destroyed or separated from the axon by disease or injury
Wallerian Degeneration
43
Causes of Ischemic cell change (5)
Causes of Ischemic cell change (5)
1. loss of blood flow
2. lack of O2 in the blood
3. lack of substrates necessary for oxidative metabolism
4. Poison (cyanide)
5. blocking oxidative metabolism
44
TRUE/FALSE
After several (2-5) minutes, cells will exhibit REVERSIBLE changes
FALSE
After several (2-5) minutes, respiratory chain processes on the inner mitochondrial membrane ceases--> ATP stores depleted--> impaired ion channels --> anaerobic glycolysis--> lactate production--> further inhibition of mitochondrial function--> IRREVERSIBLE changes
45
TRUE/FALSE
8-12 hours: the neurons become smaller; its outline more angular
TRUE
8-12 hours: the neurons become SMALLER; its outline MORE SHARPLY BLUNT
cytoplasm: eosinophilic
nucleus: shrinks and becomes darkly stained (irreversible) complete dissolution of the neuron (red, dead neuron)
46
Irreversible changes that ultimately lead to cell death
- Excitotoxicity
- Accumulation of intracellular Ca++
- Generation fo free radicals
47
Unlike in the CNS, Wallerian degeneration occurs more rapidly in the peripheral nerves? true or false
TRUE
48
Impairment of axonal transport, disappearance of neurofibrils, and breaking up of axons into short fragments that will eventually disappear
Wallerian degeneration
- Impairment of axonal transport
- Disappearance of neurofibrils
- Breaking up of axons into short fragments that will eventually disappear
49
Central Chromatolysis is seen in small motor cells. True or false?
FALSE
Center chromatolsysis is seen in LARGE motor cells:
1. spinal ventral horn cells
2. motor nuclei of cranial nerves
50
Central chromatolysis is reversible? true or false?
TRUE
can be restored in a few months
51
Center chromatolysis begins how many days after injury?
2-3 DAYS; reaches maximum in 2-3 WEEKS
52
cell is swollen, nucleus is eccentric, and Nissl granules have disappeared except at the periphery
Center Chromatolysis
Celll: swollen
Nucleus: eccentric
Nissl granules: disappeared except at the periphery
53
consists of abnormal deposits of self aggregating misfolded proteins that are an important feature of several neurodegenerstive diseases
Filamentous inclusions
54
Neuronal inclusions of neurofibrillary tangles and neuritic plaques are typical of this disease.
Alzheimer's disease
- Neurofibrillary tangles seen intranuclearly (tau proteins)
- neuritic plaques (amyloid beta peptide)
55
Cell loss and accumulation of Lewy bodies in dopaminergic neurons are characteristic of this disease
Parkinson's disease
Lewy bodies- contains alpha-synuclein
56
This is possible in PNS if the parent cell body survives but this does not occur in CNS.
Axonal regeneration
57
Rate of remyelination in the peripheral nerves per day.
1-3 mm/day
58
The reason why the CNS is not capable of axonal regeneration is because there is no basement membrane or collagen sheaths (endometrium) surrounding the nerves. True or false?
TRUE
CNS is NOT capable of axonal regeneration is because there is NO:
- basement membrane OR
- collagen sheaths (endometrium) surrounding the nerves.
59
Oligodendroglia are capable of proliferation. True or false?
False
Oligodendroglia are INCAPABLE of proliferation
60
Most common immune-related demyelinating disease
Multiple sclerosis
61
Cytoplasmic inclusions consist of accumulations of alpha synuclein
Lewy bodies
-Identified as pale 'halo'
62
intranuclear inclusions of subacute sclerosing panencephalitis
Cowdry type A
63
Lewy body @cytoplasm
Parkison disease
64
pick body @cytoplasm
Pick disease
65
Lafora body @cytoplasm
Myoclonus epilepsy
66
Negri body @cytoplasm
Rabies
67
cowdry type A inclusion @ nucleus
Viral infections
68
accumulation of metabolic products within the nerve cell
Storage cells
69
Neuron in this lipid-storage disease: ballooning of cytoplasm with stored material, forcing the nucleus and Nissl granules to one corner of the cell
Tay-Sach disease
70
2 pathologic reactions of oligodendroglia
2 pathologic reactions of oligodendroglia
1. Demyelinating or Myelonoclastic diseases
2. Leukodystrophies or dysmyelinating disease
71
Pathologic reaction of oligodendroglia: NORMAL myelin is attacked by some exogenous agent, usually unknown, and broken down into its component lipids and absorbed
Demyelinating or Myelonoclastic diseases
ex. multiple sclerosis
72
Pathologic reaction of oligodendroglia: myelin is ABNORMALLY formed owing to a genetically determined error in metabolism
Leukodystrophies or dysmyelinating disease
73
2 pathologic reactions of Schwann Cells
2 pathologic reactions of Schwann Cells
1. Segmental demyelination
2. repeated demyelination and remyelination
74
Pathologic reaction of Schwann cells:
immune-mediated disorders such as acute and chronic inflammatory neuropathies may produce segmental loss of myelin
Segmental Demyelination
ex. Guillain-Barre syndrome- Acute
75
Pathologic reaction of Schwann cells:
- Hereditary demyelinating neuropathies
- Genetic disorders affecting peripheral nerves (mutations of genes encoding for peripheral myelin proteins)
repeated demyelination and remyelination
ex. Charcot Marie-Tooth disease or HSMN 1
76
reflecting cycles of degeneration and regeneration of the myelin sheath in patient w/ hereditary sensory and motor peripheral neuropathy
Onion bulb formation
77
2 types of astrocytes
Protoplasmic and Fibrillary
78
Astrocytes predominantly in the gray and subcortical white matter
Protoplasmic astrocytes
79
shorter processes, less fibrils
Protoplasmic astrocytes
80
Astrocytes predominantly in the white matter
Fibrillary astrocytes
81
longer processes, abundant fibrils
Fibrillary astrocytes
82
TRUE/FALSE
In diseases, protoplasmic astrocytes may convert to fibrillary
TRUE
In diseases, protoplasmic astrocytes may convert to fibrillary
83
Swollen astrocyte inside the brain such as in stroke.
Gemistocytic or hypertrophied astrocyte ("PLUMP")
84
Major function is the surveillance of and participation in immunologic processes
Microglial cells
85
Rod cells, prominent in viral disease and parenchymal neurosyphilis, are distinguished by conspicuously hypertrophied rod-shaped nuclei
Activated microglia
ex. chronic encephalitis with neurosyphilis
86
TRUE/FALSE
reactive microglial cells are prominent in chronic infections
TRUE
reactive microglial cells are prominent in chronic infections
87
more likely to affect gray matter failure of Na-K pump
Cytotoxic Edema
- occurs with HYPOXIA and metabolic disorders (ex.stroke)
- primarily affects the GRAY and WHITE matter (CT scan: hypodensity areas
88
loss of integrity of the blood-brain barrier.
Vasogenic Edema
- occurs with MASS or inflammatory disease
- primarily affects the WHITE matter
89
Vasogenic edema is predominantly in the gray matter. true or false?
false
Vasogenic edema is predominantly in the white matter
90
Involving a single, circumscribed area or group of contiguous structures
Focal
91
more than one circumscribed area or several noncontiguous structures
multifocal
92
portions of the nervous system, in bilateral, symmetrical fashion
Diffuse
93
development of symptoms in minutes
Acute
94
development of symptoms within days
Subacute
95
development of symptoms within weeks/months
Chronic
96
symptoms have resolved completed after onset
Transient
97
symptoms have decreased from their maximum but not have completely resolved
improving
98
symptoms continue to increase in severity
progressive
99
symptoms remain unchanged after reaching maximum severity
stationary
100
Suggest progression of a focal lesion
mass lesion
ex. hematoma, neoplasm
101
suggest when lesion is diffuse in location or when there is non-progressive focal abnormality
Non-mass lesion
ex. meningitis, encephalitis
102
Acute and focal
vascular
infarct or intraparenchymal hgg.
103
acute and diffuse
vascular
subarachnoid hgg., anoxia
104
subacute and focal
inflammatory
abscess, myelitis
105
subacute and diffuse
inflammatory
meningitis, encephalitis
106
chronic and focal
neoplasm
107
chronic and diffuse
degenerative
108
chronic, progressive and diffuse
degenerative diseases
109
gradual decrease in neuronal function
degenerative disease
110
neurons shows specific changes
degenerative disease
111
chronic, progressive, and focal
neoplastic changes
112
Most common primary CNS tumors
Astrocytomas
113
What is the most common infratentorial tumors in children?
cerebellar medulloblastoma
114
TRUE/FALSE
in children, infratentorial tumors are common
TRUE
in children, infratentorial tumors are common
115
TRUE/FALSE
in adults, infratentorial tumors are common
FALSE
in adults, supratentorial tumors are common
116
two types of vascular disease
infarct and hemorrhagic
117
various chemical agents, vitamin deficiencies, genetic biochemical disorders and encephalopathies of kidney and liver diseases
toxic-metabolic disease
118
POST QUIZ QUESTION:
which cells proliferate in response to injury?
astrocytes
119
POST QUIZ QUESTION:
which cells myelinate the CNS?
oligodendrocytes
120
POST QUIZ QUESTION:
which does NOT produce physical changes in the cells?
a. demyelinating disease
b. infarction
c. neoplasm
d. TIA
d. TIA
121
POST QUIZ QUESTION:
chronic progressive disease
degenerative disease
122
POST QUIZ QUESTION:
capable of axonal regeneration?
a. brainstem
b. cerebrum
c. peripheral nerve
d. spinal cord
c. peripheral nerve
123
POST QUIZ QUESTION:
which cells dissolve in response to injury/?
a. astrocytes
b. fibroblasts
c. oligodendrocytes
d. microglia
c. oligodendrocytes
124
POST QUIZ QUESTION:
forms gliotic scars in the CNS?
Astrocytes
