Difference between revisions of "Neurohistology"
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==Putamen== | ==Putamen== | ||
Features: | Features: | ||
*Striatopallidal fibers [[AKA]] ''pencils of Wilson'' (also ''pencil fibers of Wilson''<ref name=Ref_PSNP23-24>{{Ref PSNP|23-34}}</ref> and ''Wilson's pencils''<ref name=pmid8985875>{{cite journal |author=Kimura M, Kato M, Shimazaki H, Watanabe K, Matsumoto N |title=Neural information transferred from the putamen to the globus pallidus during learned movement in the monkey |journal=J. Neurophysiol. |volume=76 |issue=6 |pages=3771–86 |year=1996 |month=December |pmid=8985875 |doi= |url=http://jn.physiology.org/cgi/pmidlookup?view=long&pmid=8985875}}</ref>) - bundles of blue fibres (on H&E LFB). | *Striatopallidal fibers [[AKA]] ''pencils of Wilson'' (also ''pencil fibers of Wilson''<ref name=Ref_PSNP23-24>{{Ref PSNP|23-34}}</ref> and ''Wilson's pencils''<ref name=pmid8985875>{{cite journal |author=Kimura M, Kato M, Shimazaki H, Watanabe K, Matsumoto N |title=Neural information transferred from the putamen to the globus pallidus during learned movement in the monkey |journal=J. Neurophysiol. |volume=76 |issue=6 |pages=3771–86 |year=1996 |month=December |pmid=8985875 |doi= |url=http://jn.physiology.org/cgi/pmidlookup?view=long&pmid=8985875}}</ref>) - bundles of blue fibres (on H&E LFB). | ||
*Neurons: | |||
*#Small - GABA. | |||
*#Large (very rare: ~1 in 100-200) - cholingeric. | |||
Images: | Images: | ||
| Line 117: | Line 120: | ||
*[http://commons.wikimedia.org/wiki/File:Putamen_-_intermed_mag.jpg Putamen - intermed. mag. (WC)]. | *[http://commons.wikimedia.org/wiki/File:Putamen_-_intermed_mag.jpg Putamen - intermed. mag. (WC)]. | ||
*[http://frontalcortex.com/?page=oll&topic=24&qid=760 Pencils of Wilson (frontalcortex.com)]. | *[http://frontalcortex.com/?page=oll&topic=24&qid=760 Pencils of Wilson (frontalcortex.com)]. | ||
Notes: | |||
*Histologically identical to the ''caudate'' - but not adjacent to a ventricle. | |||
**The caudate is adjacent to an ependymal lined space, putamen is not.<ref>URL: [http://www.stonybrookmedicalcenter.org/pathology/neuropathology/chapter1 http://www.stonybrookmedicalcenter.org/pathology/neuropathology/chapter1]. Accessed on: 22 December 2010.</ref> | |||
==Globus pallidus== | ==Globus pallidus== | ||
Revision as of 18:34, 22 December 2010
This article covers basic (normal) neurohistology. It is essential to have a good grasp on neurohistology and neuroanatomy... before doing neuropathology.
This article has some overlap with the neuroanatomy article, as there isn't a clear divider between microscopic and macroscopic.
Normal cells
- Neuron:
- Abundant cytoplasm - key feature.
- Often very large cells, with angled edges.
- Prominent nucleolus.
- Nissl substance (granular perinuclear material - rough ER).
- Glial cells.
- Oligodendrocyte.
- Small round nuclei (lymphocyte-like nucleus) - key feature.
- May resemble a fried egg on H&E (clear cytoplasm, central nucleus).
- Astrocyte.
- Irregular non-ovoid nucleus - key feature.
- Nuclei less dense than in oligodendrocyte.
- Close to blood vessels.
- Form blood-brain barrier.
- Cytoplasm normally not visible.
- Image: astrocyte (med.unsw.edu.au) (in endocrine development).
- Microglia - macrophage of the brain (derived from monocyte).
- May be large.
- May have vesicles.
- Rarely seen in normal tissue.
- Oligodendrocyte.
- Ependyma.
- Simple ciliated cuboidal epithelium.
- Image: Ependyma (stonybrookmedicalcenter.org).
Normal cellular constituents in a table
| Key feature | Other features | Image | |
| Neuron | cytoplasm | Nissl substance (prominent RER), "sharp" corners in cell membrane, nucleolus - usu. prominent[1] |
red neurons (WC) |
| Astrocyte | non-ovoid nucleus | no cytoplasm | (unsw.edu) |
| Oligodendrocyte | round small nucleus | peri-nuclear clearing | (vetmed.vt.edu) |
| Microglia | rod-like shape, may have "bent" nucleus |
typically have a sharply demarcated bubbly cytoplasm; rarely seen in normal tissue |
(neuropathologyweb.org), (ucsf.edu),(vcu.edu) |
Neurons
There are many types of 'em. Broadly, they can be classified as:
- Pyramidal - have a pyramidal shape.
- Dentrites go to molecular layer.
- Axons go to outside of cortex.
- Non-pyramidal.
Motor neurons:
- Coarse Nissl substance - key feature.
- Nissl described as having a tigroid appearance.[2]
- Polygonal shape.
- Send dendrites in all directions.
Image: Motor neuron (stonybrookmedicalcenter.org).
Grey vs. white matter
| Grey matter | White matter | |
| Definition | neurons present | neurons absent |
| Extracellular space (neuropil) |
dense - dark pink | fine mesh - light pink |
| Image | right 2/3 of image | left 1/3 of image |
Additional images (white matter vs. grey matter):
Histology by anatomical structure
Subependyma
Features:[3]
- Ependyma (simple ciliated cuboidal epithelium).
- Subependymal plate - connective tissue with blood vessels.
Caudate
Features:
- Neurons with adjacent ependymal lining.[4]
- The caudate forms lateral wall of lateral ventricle.
Notes:
- Caudate, putamen and nucleus accumbens are collectively called neostriatum.[5]
Putamen
Features:
- Striatopallidal fibers AKA pencils of Wilson (also pencil fibers of Wilson[5] and Wilson's pencils[6]) - bundles of blue fibres (on H&E LFB).
- Neurons:
- Small - GABA.
- Large (very rare: ~1 in 100-200) - cholingeric.
Images:
- Globus pallidus & putamen - showing Wilson's pencils - very low mag. (WC).
- Putamen - intermed. mag. (WC).
- Pencils of Wilson (frontalcortex.com).
Notes:
- Histologically identical to the caudate - but not adjacent to a ventricle.
- The caudate is adjacent to an ependymal lined space, putamen is not.[7]
Globus pallidus
Features:
- Histologically distinct from caudate and putamen.
Image: Globus pallidus, putamen and substantia innominata - very low mag. (WC).
Hippocampus
Structures
Hippocampal formation:[9]
- Dentate gyrus.
- "Dense" thin layer of nuclei.
- Quasi "U-shaped"; "open" (top) portion of "U" is superolateral.
- Image: Dentate gyrus (stonybrookmedicalcenter.org).
- Hippocampus proper (AKA Ammon's horn) - this is subdivided:
- Cornu ammonis 3 (CA3) - location: superior.
- Large pyramidal neurons.
- CA1 (AKA Sommer's sector) - location: inferior (next to subiculum).
- Small dispersed pyramidal neurons.
- CA2 - location: in between CA3 and CA1, lateral.
- Narrow band of neurons between CA3 and CA1.
- CA4 - location: medial (closest to dentate gyrus; CA4 sits in "open" part of "U").
- Cornu ammonis 3 (CA3) - location: superior.
- Subiculum (AKA subicular complex).
- Transitions to the six layers in the entorhinal cortex.
Images:
- Hippocampus - frontal section (WP).
- Hippocampus - good schematic (WC).
- Hippocampus (ajnr.org).
- Hippocampus and subiculum (hu-berlin.de).
- Hippocampus - crappy schematic (ucsd.edu).
Important notes:
- CA1 - weak link, dies in ischemia, affected by hypoglycemia, degenerative diseases and toxins.
- CA2 - resistant to ischemia.
Layers of CA[10]
- Molecular layer - opposed to the dentate gyrus (of Hippocampal formation).
- Neurons (described above).
- Alveus - opposed to the lateral ventricle.
- Connects to the mammillary bodies via the fornix (circuit of Papez).
Cerebellum
Main components:
- Cortex (superficial) - branches (Christmas tree-like).
- Dentate nucleus (deep) - looks like the bite impression of a molar.
Dentate nucleus
Features:[11]
- Ribbon of grey matter.
- Large neurons.
- Small neurons.
Cerebellar cortex
- Layers (superficial to deep) - mnemonic MPG:[12]
- Molecular layer -- "very pink" on H&E.
- Inhibitory interneurons: stellate cells, basket cells.
- Purkinje cell layer.
- One cell layer thick - hueuege cells (~50-80 micrometers[1]).
- Very large nucleus (~4x RBC diameter =~ 4x the size of granule cell).
- Large nucleolus (~1x RBC diameter =~ size of granule cell).
- Very large nucleus (~4x RBC diameter =~ 4x the size of granule cell).
- One cell layer thick - hueuege cells (~50-80 micrometers[1]).
- Granule cell layer -- "very blue" on H&E.
- Granule cells (neurons) - majority of cells, small (~10 micrometres), round.
- May look like small cell carcinoma to the uninitiated.
- Golgi cells (interneurons) - few in number, elongated/columnar, 3-5x size of granule cell.
- Granule cells (neurons) - majority of cells, small (~10 micrometres), round.
- Molecular layer -- "very pink" on H&E.
- Images:
Notes:
- Bergmann glia are found between the molecular layer & granular layer. They are normally not seen. They are increased & prominent in pathologic states (e.g. ischemia); "Bergmann gliosis".[13]
Cerebral cortex
Layers (superficial to deep):
- Molecular layer.
- Empty appearing.
- Outer granular layer.
- Higher cell density & smaller cells than pyramidal layer.
- Outer pyramidal layer.
- Inner granular layer.
- Not prominent in frontal cortex.
- Where the thalamic axons end.
- Divided in three (a, b, c) in the calcarine cortex due to two white matter bands (external band of Baillarger, internal band of Baillarger) that are grossly identified as the line of Gennari.[14]
- Image: Calcarine cortex (ouhsc.edu).[15]
- Inner pyramidal layer.
- Location of Betz neurons - large motor neurons of cerebral cortex.
- Multiforme layer (Polymorphic layer).
Images:
- Cajal drawings - different areas (WC).
- Visual cortex - low mag. (WC).
- Different stains (rice.edu).
- Cerebral cortex (williamcalvin.com).
- Cerebral cortex (benbest.com).
Pineal gland
Main article: Pineal gland
- Cells in lobulated clusters or linear arrays (low power).
- Pinealocyte:
- Light staining and round nuclei with neuroendocrine look (i.e. salt-and-pepper chromatin).
- Broad rim of light cytoplasm.
- Astrocytes:
- Cylindrical hyperchromatic nucleus ~ 1/2 the size of pinealocyte.
Images:
- Pineal gland (anhb.uwa.edu.au).[17]
- Pineal gland - very high mag. (WC).
- Pineal gland - intermed. mag. (WC).
- Pineal gland - crappy (WC).
Notes:
- Highly cellular structure - may be confused with (metastatic) small cell carcinoma.
- Often calcified.
IHC
- Synaptophysin +ve.[16]
Midbrain
Structures:
- Substantia nigra (Parkinson's disease).
- Nucleus of CN IV (posterior). (???)
- Nucleus of CN III (anterior).
- Cerebral penduncles (anterior).
Pons
Features:
- Looks like bacon (at very low power).[18]
- Images:
Locus ceruleus
- Literally means blue spot.
- Location: adjacent to midline + anterior to 4th ventricle.
Microscopic features:
- Pigmented neurons.
- Produce norepinephrine.
Medulla oblongata
- AKA medulla.
Anatomy
Schematic: Medulla - Gray's anatomy (WC).
Anterior
- Pyramids: adjacent to midline, anterior.
- Olives: lateral and posterior to pyramids.
Posterior - important nuclei (location)
- CN XII: 4th ventricle + adjacent to midline; medial to nucleus of CN X.[20]
- CN X: 4th ventricle + lateral to nucleus of CN XII.
- This is were Lewy body formation starts.[21]
See also
References
- ↑ 1.0 1.1 Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 16. ISBN 978-0443069826.
- ↑ URL: http://www.stonybrookmedicalcenter.org/pathology/neuropathology/chapter1. Accessed on: 5 July 2010.
- ↑ Croul SE. 28 June 2010.
- ↑ URL: http://www.stonybrookmedicalcenter.org/pathology/neuropathology/chapter1. Accessed on: 2 July 2010.
- ↑ 5.0 5.1 Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 23-34. ISBN 978-0443069826.
- ↑ Kimura M, Kato M, Shimazaki H, Watanabe K, Matsumoto N (December 1996). "Neural information transferred from the putamen to the globus pallidus during learned movement in the monkey". J. Neurophysiol. 76 (6): 3771–86. PMID 8985875. http://jn.physiology.org/cgi/pmidlookup?view=long&pmid=8985875.
- ↑ URL: http://www.stonybrookmedicalcenter.org/pathology/neuropathology/chapter1. Accessed on: 22 December 2010.
- ↑ Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 23. ISBN 978-0443069826.
- ↑ URL: http://www.stonybrookmedicalcenter.org/pathology/neuropathology/chapter1. Accessed on: 2 July 2010.
- ↑ Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 25. ISBN 978-0443069826.
- ↑ Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 27. ISBN 978-0443069826.
- ↑ URL: http://www.stonybrookmedicalcenter.org/pathology/neuropathology/chapter1. Accessed on: 2 July 2010.
- ↑ Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 18. ISBN 978-0443069826.
- ↑ Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 24. ISBN 978-0443069826.
- ↑ URL: http://moon.ouhsc.edu/kfung/iacp-olp/apaq-text/N1-MS-01-01-Ans.htm and http://moon.ouhsc.edu/kfung/iacp-olp/apaq-text/n1-ms-01.htm. Accessed on: 31 October 2010.
- ↑ 16.0 16.1 Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 25-26. ISBN 978-0443069826.
- ↑ 17.0 17.1 URL: http://www.lab.anhb.uwa.edu.au/mb140/corepages/endocrines/endocrin.htm. Accessed on: 31 October 2010.
- ↑ Croul SE. 28 June 2010.
- ↑ URL: http://www.med.univ-rennes1.fr/etud/pharmaco/media/alzheimerGB.htm#Locus%20coeruleus. Accessed on: 4 December 2010.
- ↑ Crossman, Alan R.; Neary, David. (2010). Neuroanatomy: An Illustrated Colour Text (4th ed.). Churchill Livingstone. pp. 13. ISBN 978-0702030864.
- ↑ Miller VM, Kenny RA, Oakley AE, Hall R, Kalaria RN, Allan LM (August 2009). "Dorsal motor nucleus of vagus protein aggregates in Lewy body disease with autonomic dysfunction". Brain Res. 1286: 165–73. doi:10.1016/j.brainres.2009.05.083. PMID 19501577.