Table of Contents

TISSUE FIXATION
- TISSUE FIXATIVES

TISSUE FIXATION

Tissue fixation
- aim and objectives of fixation
  - prevent autolysis and putrefaction of sample
  - cause
    - coagulation of tissue
      - to prevent loss of diffusible substances
      - stabilization of proteins
  - to fortify or increase strength of tissue specimen
  - to make favorable condition for stains
- tissue fixatives or chemical fixatives
  - Crosslinking fixatives – aldehydes
    - formaldehyde or formalin
    - glutaraldehyde
  - Precipitating (denaturing ) fixatives – alcohols
    - Ethyl Alcohol
    - methanol ( sometimes)
  - oxidising agents
    - for histology
      - potassium dichromate
      - potassium permanganate
      - chromic acid
    - for electron microscopy
      - osmium tetroxide
  - mercurials
    - use
      - increases staining brightness
      - but slow permeability
    - types
      - mercuric chloride
      - zenker's fixative
  - Picrates
  - bouins fluid
  - Karnovsky fixative

TISSUE FIXATIVES

Formaldehyde or formalin

bouins fluid

Glutaraldehyde

Mercuric chloride

Potassium Dichromate

Ethyl Alcohol