18 Questions
What is the recommended duration of formalin fixation?
2 to 6 hours
What is the ideal volume of fixative in relation to tissue volume for maximum effectiveness?
20 times the tissue volume
What are the characteristics of a good fixative based on the text?
Cheap, stable, safe to handle
What effect do fixatives have on tissues based on the text?
Hardens tissues for easy handling
What should be done if autopsy materials cannot be fixed immediately?
Place in a mortuary refrigerator at 4°C
What happens if fixation is prolonged according to the text?
Tissue hardens and shrinks
What is the main goal of fixation in histotechnology?
Preserve morphologic and chemical integrity of cells
Which type of fixation involves the fixing agent becoming part of the tissue by forming cross links?
Additive fixation
What is the ideal pH range for fixation in histotechnology?
pH 6 to 8
In what temperature range are tissues processed for electron microscopy fixation?
40°C
What effect does hypertonic fixative have on cells during fixation?
Cell shrinkage
What is the recommended concentration of glutaraldehyde for immuno electron microscopy fixation?
0.5%
What is the purpose of placing a primarily fixed tissue in a 2.5 - 3% potassium dichromate solution for 24 hours?
To act as a mordant for better staining
Which solution is used to wash out excess chromates from tissues fixed in Kelly’s, Zenker’s, and Flemming solutions?
Tap water
What factor enhances the process of fixation?
Agitation
How does cold temperature affect fixation?
Inactivates enzymes
Which type of fixative is known as a microanatomical fixative?
Heidenhain’s Susa Formol Sublimate
Why is washing out tap water used after fixing tissues?
To remove excess formalin and osmic acid
Learn about the duration, speed, penetration, volume, and general effects of tissue fixation in histology. Understand how fixation affects tissues and the importance of proper fixation techniques.
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