Nervous Tissue Staining Flashcards
What are the two anatomical sections of the nervous system?
a) CNS – brain and spinal cord
b) PNS – all other nervous tissue
What is the somatic nervous system responsible for?
Voluntary, conscious control
What is the autonomic nervous system responsible for?
Involuntary functions
What are the three categories of nervous tissue stains?
- Nervous tissue cells and processes
- Glial cells and processes
- Myelin sheath
What does Nissl substance consist of?
Basophilic cytoplasmic material found in neurons (RNA)
What staining methods are used for Nissl substance?
- Cresyl echt
- Thionin (aniline dyes)
What are the two types of nerve cell processes?
- Axons
- Dendrites
What is the function of dendrites?
Main location for neuron information input
What is the purpose of neuroglia?
Support and insulate neurons in the CNS
What are the four types of glial cells?
- Oligodendroglia
- Astroglia
- Microglia
- Ependymal cells
What do oligodendroglia do?
Produce myelin sheath in the CNS
What is the main role of astrocytes?
Provide physical and nutritional support for neurons
What are microglia?
Phagocytic cells located in the brain and spinal cord
What is the role of ependymal cells?
Form a selective barrier between CSF and neural tissue
What is myelin composed of?
- Protein
- Cerebrosides
- Phospholipids
- Cholesterol
What staining method is commonly used for myelin sheath?
Luxol Fast Blue and iron hematoxylin
What is the result of the osmium tetroxide method?
Myelin stained black
What is Weigert’s method used for?
To stain myelin blue
What is the purpose of the Luxol Fast Blue method?
To demonstrate normal myelin
What type of staining method is Luxol Fast Blue?
Regressive staining method
What is the fixative of choice for Luxol Fast Blue?
10% formalin or K dichromate
What are the results expected from a Luxol Fast Blue stain?
- Myelin fibers stain blue
- Nissl substance purple to violet
- Nuclei purple to violet
What is the purpose of Weil’s method?
For the demonstration of myelin in tissue
What does Mallory’s PTAH stain demonstrate?
Glial cells
What is the principle of the Mallory’s PTAH stain?
Phosphotungstic acid binds hematein to provide a blue stain
What is the fixative used in Mallory’s PTAH?
10% NBF
What is the significance of the staining solution in Mallory’s PTAH?
It stains astrocytes blue
How long should sections be decolorized in 95% alcohol?
At least one hour
What is the first step after decolorizing sections in 95% alcohol?
Rinse rapidly in 3 changes of distilled water
How long should sections be washed in running tap water after staining with KMnO4?
10 minutes
How long should sections be stained in PTAH solution?
Overnight at RT
In the PTAH staining results, what color do glial cells appear?
Blue
What color do neurons stain in the PTAH method?
Salmon
Which method demonstrates astrocytes?
Cajal’s method
What type of fixative is used for the Cajal method?
Formalin ammonium bromide
What is the Bielschowsky method used for?
To stain neurofibrils
What are the two types of myelin stains?
- Positive methods (staining degenerating myelin)
- Negative methods (staining normal myelin)
What are examples of negative myelin stains?
- Luxol Fast Blue
- Weil’s methods
What is a potential hazard of using mercuric chloride?
Extremely toxic and a severe environmental hazard
