Histology Spring 2020 > Chapter 9: Nerve > Flashcards

Chapter 9: Nerve Flashcards

(106 cards)

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1
Q

Cresyl Echt Violet 1 Purpose

A

Identification of neurons or demonstration of lost Nissl substance that indicates neuronal injury

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2
Q

Cresyl Echt Violet 1 Principle

A

Nissl substance is very basophilic due to RNA content, and therefore stains sharply with basic aniline dyes
Adjusting pH can show both Nissl and nuclei or only Nissl

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3
Q

Cresyl Echt Violet 1 Preferred Fixative

A

10% NBF

Spinal cord control

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4
Q

Cresyl Echt Violet 1 Basic Procedure

A
  1. Deparaffinize, hydrate
  2. Stain in cresyl echt violet (ripen for 24-48 hours and filter before use)
  3. Rinse in distilled water
  4. Place sections in 95% alcohol
  5. Transfer sections to absolute alcohol
  6. Place in xylene
  7. Place in balsam-xylene mixture
  8. Differentiate in absolute alcohol, check sections microscopically
  9. Several changes of xylene
  10. repeat 7-9 multiple times until differentiation is complete; background should be colorless and blue to purple nuclei and Nissl
  11. Coverslip
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5
Q

Cresyl Echt Violet 1 Results

A

Nissl substance and nuclei: blue to purple

background: colorless

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6
Q

Cresyl Echt Violet 1 Technical notes

A

Differentiation should be repeated until the background is colorless. This usually requires several repetitions

The alcohol following the balsam-xylene mixture will become cloudy and should be changed frequently

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7
Q

Cresyl Echt Violet 2 Purpose

A

Identify neurons or loss of Nissl substance (chromatolysis)

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8
Q

Cresyl Echt Violet 2 Principle

A

Same as method one, but the cresyl echt violet is at an acidic pH which enhances contrast between the background and Nissl or nuclei

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9
Q

Cresyl Echt Violet 2 Preferred Fixative

A

10% NBF

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10
Q

Cresyl Echt Violet 2 Basic Procedure

A
  1. Deparaffinize, hydrate
  2. stain in acidic cresyl echt violet (includes alcohol and acetic acid)
  3. Dehydrate, clear, coverslip
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11
Q

Cresyl Echt Violet 2 Results

A

Nissl substance and nuclei: blue-purple

Background: colorless

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12
Q

Cresyl Echt Violet 2 Technical notes

A

Macroscopically the slides will appear unstained

Cresyl echt violet from Luxol fast blue stain may also be used to identify Nissl substance

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13
Q

Bodian Method Purpose

A

Stain nerve fibers

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14
Q

Bodian Method Principle

A
  1. Protargol (brand name silver proteinate) impregnates tissue
  2. Copper is added to impregnating solution to “destain” connective tissue to improve differentiation
  3. Hydroquinone reduces the deposited silver salts into visible metallic silver
  4. Gold chloride is the toner (oxalic acid can be used to reduce the gold and intensify the stain)
  5. Sodium thiosulfate removes unreduced silver
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15
Q

Bodian Method Preferred Fixative

A

10% NBF

Control: peripheral nerve or cerebral cortex to avoid cross-section

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16
Q

Bodian Method Basic Procedure

A
  1. Deparaffinize, hydrate
  2. Add clean copper shot to Protargol at 37C for 48 hours
  3. Rinse in distilled water
  4. place in reducing solution
  5. Rinse in water
  6. Tone in gold chloride
  7. rinse in water
  8. Develop in Oxalic Acid, checking microscopically until the background is grey and the nerve fibers appear clearly stained. Don’t treat too long or it will ruin the silver
  9. Rinse in water
  10. Treat with sodium thiosulfate to remove unreduced silver
  11. Rinse in distilled water
  12. Counterstain, if desired, with aniline blue
  13. Dehydrate, clear, coverslip
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17
Q

Bodian Method Results

A

Nerve fibers and nuclei: black

Background: light grey or blue (if counterstained)

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18
Q

Bodian Method Technical notes

A

Copper shot is cleaned with aqua regia (HCl +Nitric Acid). After use it should be gradually poured into a very large volume of water and then discarded in the sink. Do not pour directly into sink, do not add water to the acid.

Protargol should be left undisturbed until it is completely dissolved

use chemically clean glassware and non-metallic forceps
Don’t overcounterstain with Aniline blue

You can also use nuclear fast red as a counterstain

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19
Q

Holmes Silver Nitrate Method Purpose

A

Demonstrate nerve fibers and neurofibrils

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20
Q

Holmes Silver Nitrate Method Principle

A

Bodian doesn’t work well because the Protargol solution never reaches necessary alkalinity for proper impregnation. Holmes developed a buffered impregnation solution

This is an argyrophil silver method that requires chemical reduction
Gold chloride toner, Oxalic acid reducer, and sodium thiosulfate are the same as in Bodian

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21
Q

Holmes Silver Nitrate Method Preferred Fixative

A

10% NBF
Control: peripheral nerve or cerebral cortex to avoid cross-section
10-15uM paraffin

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22
Q

Holmes Silver Nitrate Method Basic Procedure

A
  1. Deparaffinize, hydrate
  2. Place in 20% silver nitrate in the dark
  3. Prepare impregnating solution (Boric acid, Borax, water, silver nitrate, pyridine)
  4. Wash slides in distilled water
  5. Place slides in impregnating solution overnight at 37C
  6. Remove slides, shake of excess fluid, and place in reducer (hydroquinone, sodium sulfite, water)
  7. wash in running water
  8. Rinse in distilled water
  9. Tone in gold chloride (can be re-used until brown precipitate forms or the solution becomes cloudy)
  10. Rinse in distilled water
  11. Place slides in oxalic acid, when the axons are thoroughly blue-black, stop the process
  12. Rinse in distilled water
  13. place in sodium thiosulfate
  14. wash in tap water. Counterstain if desired
  15. Dehydrate, clear, coverslip
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23
Q

Holmes Silver Nitrate Method Results

A

Axons and nerve fibers: black

Neurofibrils: black

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24
Q

Holmes Silver Nitrate Method Technical notes

A

Pyridine is toxic by ingestion, inhalation, and skin absorption. Use under a fume hood with gloves and goggles

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25
Bielschowsky-PAS Purpose
To demonstrate nerve fibers, neurofibrillary tangles, and senile plaques in Alzheimer disease
26
Bielschowsky-PAS Principle
1. impregnate with ammoniacal silver which deposits on neurofibrils and axons 2. silver is reduced to metallic silver by formaldehyde in the developer 3. Gold chloride tones the tissue and removes yellow 4. sodium thiosulfate removes unreduced silver background 5. schiff reaction (PAS) stains basement membranes and amyloid in the plaques
27
Bielschowsky-PAS Preferred Fixative
10% NBF | Control: CNS tissue containing plaques and tangles
28
Bielschowsky-PAS Basic Procedure
1. Prepare ammoniacal silver solution 2. Deparaffinize, hydrate 3. Place in silver nitrate solution in the dark at room temp 4. Wash with distilled water 5. Place in ammoniacal silver solution 6. Wash in ammonia water 7. While slides are in ammonia water, add 2 drops of developer to the ammoniacal silver solution from step 5 8. place slides in ammoniacal/developer solution. The tissue should turn brown in about 3 minutes 9. Wash well in ammonia water, then distilled water 10. Tone in gold chloride until grey appears 11. Wash in ammonia water, then rinse in distilled water 12. Place in sodium thiosulfate 13. Wash in running tap water 14. Rinse well in distilled water 15. Place sections in 1% periodic acid 16. Rinse in distilled water 17. Place in schiff reagent 18. Wash in tap water 19. Dehydrate, clear, coverslip
29
Bielschowsky-PAS Results
Neurofibrillary tangles: dark black Peripheral neurites and plaques: dark black Axons: black Amyloid (plaque cores and vasculature): magenta Lipofuchsin: magenta
30
Bielschowsky-PAS Microwave Purpose
Demonstrate nerve fibers, tangles, and plaques in Alzheimer's
31
Bielschowsky-PAS Microwave Principle
Sections are not toned with gold chloride so yellow background remains
32
Bielschowsky-PAS Microwave Preferred Fixative
10% NBF | Control: CNS with plaques and tangles
33
Bielschowsky-PAS Microwave Basic Procedure
1. Deparaffinize, hydrate 2. Place slides in 1% Silver Nitrate, dip several times and incubate in warm solution for 15 minutes 3. Place slides in distilled water 4. 1% silver nitrate from step 2 + 28% ammonium drops until precipitate clears, then 5% silver nitrate drops until solution becomes slightly cloudy 5. microwave slides in the solution, dip slides and incubate in warm solution 6. Place slides in 1% ammonium hydroxide 7. add 3 drops developer to ammoniacal silver from step 5, place slides in solution until tissue turns brown 8. Place slides in 1% ammonium hydroxide 9. Rinse in distilled water 10. Wipe silver mirror off both sides of slide without disturbing the tissue 11. place slides in 2% sodium thiosulfate 12. Rinse slides in distilled water 13. Dehydrate, clear, coverslip
34
Bielschowsky-PAS Microwave Results
``` Axons: brown to black Cytoplasmic neurofibrils: brown to black Tangles and plaques: dark brown or black Neuromelanin: black Lipofuchsin: brown or black ```
35
Bielschowsky-PAS Microwave Technical notes
Use chemically cleaned glassware, non-metallic forceps Uses much less silver nitrate than traditional Bielschowsky and stains tangles and plaques better
36
Sevier-Munger Modification of Bielschowsky Purpose
Demonstrate nerve fibers, tangles, and plaques for Alzheimer's
37
Sevier-Munger Principle
Ammoniacal silver impregnation Reduced by formaldehyde developer No toning with gold chloride so yellow background remains Sodium Thiosulfate removes unreduced silver
38
Sevier-Munger Preferred Fixative
10% NBF Control: CNS with tangles and plaques 6-8uM sections
39
Sevier-Munger Basic Procedure
1. Deparaffinize, hydrate 2. Preheat 20% silver nitrate, then add slides to warm silver solution and incubate in the oven 3. Rinse one slide at a time in distilled water and place in a clean, dry staining jar 4. add 10 drops formalin, while agitating, to working ammoniacal silver solution, pour over slides and develop until golden brown. Check microscopically, do not wash while checking, keep in motion while developing to avoid precipitation 5. Rinse slides well in tap water 6. Place in sodium thiosulfate 7. Wash well in tap water 8. Dehydrate, clear, coverslip
40
Sevier-Munger Results
Nerve endings and neurofibrils: black | Tangles, peripheral neurites, and plaques: black
41
Sevier-Munger Technical notes
Very reliable and reproduce-able technique Concentration of ammonium hydroxide and formalin are critical leave a few particles of silver, do not add extra ammonia This is an argyrophil stain that is also useful fro demonstrating the granules of some carcinoid tumor cells
42
Thioflavin S (modified) Purpose
Demonstrates presence of tangles, plaques, threads in addition to parenchymal and amyloid deposition in Alzheimer's disease
43
Thioflavin S (modified) Principle
Fluorescent visualization of amyloid Pretreatment with potassium permanganate, and bleaching with potassium metabisulfate and oxalic acid Treatment with sodium hydroxide and hydrogen peroxide, which remove lipid autofluorescence for better definition of pathological lesions Visualization is better than routine Thioflavin S ans is not affected by prolonged fixation More sensitive than silver methods Faster and cheaper than silver
44
Thioflavin S (modified) Preferred Fixative
10-20% NBF Control: CNS with plaques and tangles 6um sections air dried overnight, then 10 minutes in 60C oven
45
Thioflavin S (modified) Basic Procedure
1. Deparaffinize, hydrate 2. Rinse and old in distilled water 3. cover tissue with 0.25% potassium permanganate 4. wash slides in running tap water 5. treat slides with 1% potassium bisulfate 6. wash in running tap water 7. place in sodium hydroxide-peroxide 8. wash in running tap water and then filtered water 9. place slides in 0.25% acetic acid 10. wash slides in running tap water 11. place slides in 50% alcohol 12. place in Thioflavin S 13. rinse slides in 50% alcohol with agitation 14. Rinse in 95% alcohol 15. completely dehydrate in absolute alcohol and clear in xylene. Mount with non-fluorescent mounting medium 16. View slides on a fluorescent filter set that incorporates a blue-violet excitation filter
46
Thioflavin S (modified) Results
tangles, neurites, threads, plaque amyloid, and cerebrovascular amyloid: bright green Diffuse plaques and extracellular plaques: paler yellow green PSP tangles and Pick bodies: not well demonstrated
47
Thioflavin S (modified) Technical notes
Float tissue on pre-heated DI water bath Mount sections with cytoseal 60 Staining is stable for several months at room temp
48
PTAH Purpose
Demonstration of glial fibers (also used to demonstrate muscle striations)
49
PTAH Principle
High ratio of PTA to hematein 20:1 so that tungsten binds all available hematein to form a blue lake which stains glial fibers, nuclei, and myelin. Red brown or salmon color of neurons is due to the PTA alone. Overuse of alcohol will fade the red-brown
50
PTAH Preferred Fixative
10% NBF 6-8uM sections Control: Cerebral cortex (not spinal cord)
51
PTAH Basic Procedure
1. Deparaffinize, hydrate 2. Mordant the sections overnight at room temp in Zenker solution containing acetic acid 3. Wash sections in running water 4. Place in Lugol Iodine. Do not use sodium thiosulfate because it may impair subsequent staining 5. Decolorize the sections in 95% alcohol for 1 hour 6. Rinse rapidly in distilled water 7. Place in 1% potassium permanganate 8. Wash in running tap water 9. Decolorize the sections in 5% oxalic acid 10. Wash in running tap water 11. Stain in PTAH overnight 12. Dehydrate, clear, coverslip
52
PTAH Results
Glial fibers: blue Nuclei: blue Neurons: salmon Myelin: blue
53
PTAH Technical notes
Replaced by immunohistochemical methods Don't over rinse in EtOH Don't use sodium thiosulfate or stain won't work
54
Holzer Method Purpose
To demonstrate glial fibers and areas of gliosis (glial damage)
55
Holzer Method Principle
Glial fibers are stained with crystal violet and are resistant to decolorization with an alkaline aniline-chloroform mixture
56
Holzer Method Preferred Fixative
10% NBF 6-8uM sections Control: Cerebral cortex, not spinal cord
57
Holzer Method Basic Procedure
1. Deparaffinize, hydrate 2. place in PMA-alcohol 3. Drain off excess fluid, place slides in a staining rack and cover the sections with absolute alcohol-chloroform mixture. The tissue should become translucent 4. While sections are still wet, cover them with the crystal violet stain 5. Replace the stain with 10% potassium bromide 6. Blot the sections dry and then allow them to air dry 7. Differentiate in aniline-oil+chloroform+ammonium hydroxide differentiating solution 8. Wash in several changes of xylene. Repeat steps 7 and 8 until the background is very pale or colorless 9. Mount with synthetic resin
58
Holzer Method Results
Glial fibers: blue | Background: very pale blue to colorless
59
Holzer Method Technical notes
Crystal Violet precipitate may be removed with straight aniline oil Aniline oil and chloroform are both very hazardous; use in a chemical fume hood The aniline oil-chloroform-ammonium hydroxide differentiating solution resists decolorization
60
Cajal Method Purpose
Demonstrate astrocytes
61
Cajal Method Principle
Astrocytes are selectively stained with the Cajal gold sublimate method on frozen sections
62
Cajal Method Preferred Fixative
Formalin ammonium bromide for 2-25 days, rinse and place in formalin ammonium bromide for 2 days if previously fixed with 10% NBF 20-30uM Sections, free floating, no slides Control: cerebral cortex, not spinal cord
63
Cajal Method Basic Procedure
1. wash free floating frozen sections in several changes of distilled water 2. Transfer the sections to the gold sublimate solution (gold chloride + mercuric chloride) and incubate in the dark for 4 hours, sections should turn purple 3. Wash well in distilled water 4. Treat with 5% sodium thiosulfate 5. Wash in distilled water 6. Carefully mount the sections on slides, blot and dehydrate 7. Clear in xylene and mount with synthetic resin
64
Cajal Method Results
Astrocytes: black
65
Cajal Method Technical notes
Tissue sections better if washed in tap water for 30 minutes before freezing chemicals must be pure; brown chloride is preferred over yellow gold chloride Protoplasmic (grey matter) astrocytes lose stainability after prolonged fixation Staining solution should not exceed 30C mixture of mercuric chloride and gold chloride is essential for astrocyte demonstration mercuric chloride is extremely toxic and an environmental hazard
66
Weil's Purpose
Demonstration of myelin Myelin degeneration, such as in syphilis
67
Weil's Principle
Mordant-hematoxylin solutions attaches to the phospholipid component of the myelin sheath, which has an affinity for the cationic (+) lake Regressive technique 1. Ferric ammonium sulfate: excess mordant differentiation removes most of the excess dye 2. Borax ferricyanide: oxidizer differentiation which removes any remaining non-specifically bound hematoxylin lake and forms a colorless oxidation product. Only myelin sheath and red blood cells remain stained
68
Weil's Preferred Fixative
10% NBF 10-15uM Sections Control: Spinal cord or medulla
69
Weil's Basic Procedure
1. Deparaffinize, hydrate 2. Transfer sections to staining solution for 30 minutes at 54-56C 3. Wash in tap water 4. Differentiate in 4% ferric ammonium sulfate until the gray matter can just be distinguished from the white matter and the stain is removed from the slides 5. Wash in tap water 6. Complete differentiation in the sodium borate-potassium ferricyanide solution. This should be checked until the grey and white matter are sharply defined 7. Wash in tap water 8. Treat sections in diluted ammonia water 9. Wash in distilled water 10. Dehydrate, clear, coverslip
70
Weil's Results
Myelin sheath: blue to blue-black | Background: light tan
71
Weil's Technical notes
Gray matter and demyelinated white matter should appear light brown and contrast sharply with blue-black myelinated white matter Easy macroscopic differentiation Naturally ripen for 6 months or chemically ripen with ferric ammonium sulfate
72
Luxol Fast Blue Purpose
Demonstrate myelin
73
Luxol Fast Blue Principle
Similar to alcian blue, but is alcohol rather than water soluble. Staining is accomplished through an acid-base reaction in which the base of the myelin lipoprotein swaps with the base of the dye
74
Luxol Fast Blue Preferred Fixative
10% NBF 10-15uM Sections Control: spinal cord or medulla
75
Luxol Fast Blue Basic Procedure
1. Deparaffinize, hydrate 2. Place slides in LFB (Luxol Fast Blue) and incubate overnight at 56-58C 3. Rinse in 95% alcohol to remove excess stain (LFB is alcohol soluble) 4. Rinse in water 5. Begin differentiating by immersing slides in lithium carbonate solution 6. Continue differentiation in 70% alcohol until gray matter and white matter can be distinguished. Do not over differentiate 7. Wash in distilled water 8. Finish differentiation by rinsing briefly in lithium carbonate and then through several changes of 70% alcohol until the greenish blue of the white matter contrasts sharply with colorless grey matter 9. Rinse in distilled water 10. Dehydrate, clear, coverslip
76
Luxol Fast Blue Results
Myelin: blue to blue-green Background: colorless
77
Luxol Fast Blue Technical notes
Gray matter and demylinated white matter should be almost colorless and contrast sharply with blue stained myelinated white matter Quality of the stain (contrast) can be determined macroscopically Differentiate until gray matter is almost colorless
78
LFB-Holmes silver nitrate Purpose
Demonstrate myellin and nerve fibers in the same section
79
LFB-Holmes silver nitrate Principle
LFB staining is accomplished through an acid-base reaction in which the base of the myelin lipoprotein swaps with the base of the dye Holmes is an argyrophil silver method that requires chemical reduction Gold chloride toner, Oxalic acid reducer, and sodium thiosulfate
80
LFB-Holmes silver nitrate Preferred Fixative
10% NBF 10-15uM Sections Control: Cerebral cortex or longitudinal section of peripheral nerve
81
LFB-Holmes silver nitrate Basic Procedure
1. Deparaffinize, hydrate 2. 20% silver nitrate in the dark at room temp 3. make impregnating solution (boric acid+borax+silver nitrate+pyradine) 4. Take slides out of 20% silver nitrate and wash in distilled water 5. 37C overnight incubation in impregnating solution 6. shake off excess fluid, and place in reducer (hydroquinone+sodium sulfite) 7. Wash in running water, then distilled water 8. Tone in gold chloride. Solution may be reused until a brown precipitate forms or the solution becomes cloudy 9. Rinse in distilled water 10. Place in oxalic acid, stop when sections are blue-black 11. Rinse in distilled water 12. Place slides in sodium thiosulfate 13. Wash in tap water 14. place in 95% alcohol 15. Stain in LFB overnight at 60C 16. place in 95% alcohol 17. Place in distilled water 18. Place in lithium carbonate 19. Differentiate in 70% alcohol 20. Rinse in distilled water (repeat steps 18-20 until desired differentiation is achieved) 21. Dehydrate, clear, coverslip
82
LFB-Holmes silver nitrate Results
Myelin: blue to green | Axons and nerve fibers: black
83
LFB-cresyl echt violet Purpose
Demonstrate both myelin and Nissl substance
84
LFB-cresyl echt violet Principle
LFB staining is accomplished through an acid-base reaction in which the base of the myelin lipoprotein swaps with the base of the dye Cresyl echt violet uses a basic aniline dye to stain RNA blue, thus demonstrating the RNA in the rough endoplasmic reticulum which comprises the Nissl substance
85
LFB-cresyl echt violet Preferred Fixative
10% NBF 10-15uM sections Control: spinal cord or medulla
86
LFB-cresyl echt violet Basic Procedure
1. Deparaffinize, hydrate 2. Place slides in LFB, incubate overnight in 56-58C 3. rinse in 95% alcohol to remove excess stain 4. Rinse in distilled water 5. Begin differentiation by immersion in lithium carbonate 6. Continue differentiation in 70% alcohol until grey and white matter can be distinguished 7. Rinse in distilled water 8. Finish differentiation by rinsing briefly in lithium carbonate and then through several changes of 70% alcohol until sharp contrast is achieved 9. Rinse in distilled water 10. Add acetic acid, filter, and preheat cresyl echt violet. Place slides in cresyl echt violet for 6 minutes, keep warm while staining. 11. Differentiate in several changes of 95% alcohol 12. Dehydrate, clear, coverslip
87
LFB-cresyl echt violet Results
Myelin: blue (from LFB) Nissl substance: violet (from cresyl) Nuclei: violet (from cresyl)
88
LFB-cresyl echt violet Technical notes
If you don't add acetic acid to the CEV, you will get a diffuse violet background stain Staining of Nissl will be reduced if you don't heat the CEV prior to staining CEV counterstain intensifies the myelin sheath stain
89
LFB-PAS-Hematoxylin Purpose
Demonstrate myelin sheath, basement membranes, senile plaques, fungi, and corpora amylacea The various stains sharpen and complement each other
90
LFB-PAS-Hematoxylin Principle
LFB staining is accomplished through an acid-base reaction in which the base of the myelin lipoprotein swaps with the base of the dye Periodic acid oxidizes reactive groups to form aldehydes (-CHO) Basic fuschin + sulfurous acid = leucofuschin/Schiff's reagent which binds to exposed aldehyde groups Water washes away the sulfur resulting in the rose chromophore
91
LFB-PAS-Hematoxylin Preferred Fixative
10% NBF 10-15uM Sections Control: Cerebral cortex or medulla
92
LFB-PAS-Hematoxylin Basic Procedure
1. Deparaffinize, hydrate 2. Incubate in LFB overnight at 56-58C 3. Rinse in 95% alcohol to remove excess stain 4. Rinse in distilled water 5. Begin differentiation by placing in lithium carbonate 6. Continue differentiation in 70% alcohol until grey and white matter become distinguished 7. Wash in distilled water 8. Finish differentiation by rinsing briefly in lithium carbonate and then through several changes of 70% alcohol until sharp contrast is achieved (repeat 7-8 as necessary) 9. Rinse in distilled water 10. Place in periodic acid (aldehyde formation) 11. Place in distilled water 12. Place in schiff solution 13. Wash in tap water 14. Stain with Harris hematoxylin 15. Wash in tap water (if background is not clear dip once in acid-alcohol and wash, if nuclei are not dark blue to purple dip briefly in dilute ammonium hydroxide and wash) 16. Dehydrate, clear, coverslip
93
LFB-PAS-Hematoxylin Results
``` Capillary basement membranes: Rose Fungi: Rose Corpora amylacea: Rose Senile plaques: Rose Myelin Sheath: Blue to blue-green Nuclei: purple ```
94
Two anatomic parts of the nervous system
CNS: brain and spinal cord PNS: everything else
95
2 functional parts of the nervous system
Somatic: voluntary Autonomic: involuntary
96
3 groups of nervous system stains based on stain target
Neuronal cell bodies and processes Glial cells and processes Myelin sheath
97
Neuron
Cellular unit of the nervous system, conduct information vial electrochemical impulses
98
What are the structural components of a neuron?
``` Cell body containing nucleus Dendrites Axon Myelin sheath Node of Ranvier ```
99
Characteristics of Nissl Substance
Basophilic: stains blue/black with hematoxylin, or basic aniline dyes like thionin and cresyl echt violet Large aggregates of rough endoplasmic reticulum with RNA content being stained
100
Neuroglia
"Nerve glue" like a connective tissue for the CNS Insulate neurons except at synapses produce the myelin sheath
101
4 types of glial cells
Oligodendroglia/oligodendrocytes Astrocytes Microglia Ependymal Cells
102
Oligodendroglia
Produce and maintain myelin sheath in the CNS
103
Astrocytes
Protoplasmic(gray) and fibrous(white) help in scar formation after brain injury support nerve fibers Star shaped (stellate)
104
Microglia
fixed phagocytic cells found throughout the brain and spinal cord (immune response)
105
Ependymal Cells
Epithelium with a brush border that acts as the blood/brain barrier
106
Myelin
Fatty insulation around neurons Stains with lipid stains Deposited by oligodendrocytes on multiple neurons in the CNS Deposited by Schwann cells on individual neurons in the PNS Typically demonstrated with Luxol fast blue and iron hematoxylin
Histology Spring 2020
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