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Fixation and Fixatives: Roles and Functions - Coggle Diagram
Fixation and Fixatives: Roles and Functions
Definition
physiochemical process in which cells
or tissues are fixed chemically
Functions
Making tissue firm
Help make the tissue more easily permeable
for subsequent reagents
Preventing osmotic damage of tissues
emphasizing the
dissimilarity in refractive index
Conserving the association in between cells and extracellular substances
Prevent autolysis (enzymes attack) and putrefaction (bacterial attack) of tissues.
Factors
Temperature
0°to 4°C
Concentration
Fixative agents need prolonged time for fixation if concentration is low. If concentrations of fixing agent are high, it
results in damaging of cellular structures as well as obliterated enzyme activities.
Length of fixation
overnight fixation is sufficient
Size
4- to 6-mm-thick
Osmolarity
Prevent swelling or shrinkage of the tissue
Fixating Agents used in Histopathology
Glutaraldehyde
Ethanol and Methanol
Formaldehyde or Formalin
Acetone
Mercuric Chloride
Glyoxal
Osmium Tetroxide
Acetic Acid
Potassium Dichromate
Bouin’s Fixative
Acrolein
Genipin