IMED1001 Study Guide - Final Guide: Haematoxylin, Xylene, Microtome
IMED1001'Tutorial'Week'1'Summary'
'
Histology)Lab:)
)
è USE'LIGHT'MICROSCOPE)
è Preparation'process:'paraffin'embedding'process)
è Thickness:'5-8'microns')
'
Preparation'of'histological'sections:''
1) Collection'of'tissue'
2) Fixation'
- uses'formalin'
- makes'tissues'firm'
- preserves'tissue,'stops'decomposition'&'autolysis'
3) Dehydration'
- uses'alcohol'
- removes'water'
- immerse'tissue'in'increasing'strength'of'ethyl'alcohol'
- ='tissues'may'shrink'
4) Clearing'
- replace'alcohol'with'paraffin'solvent'(carcinogenic)'
- eg'of'paraffin'solvent:'toluene,'benzene,'xylene'
- removes'fat'
5) Infiltration'
- dip'tissue'in'molten'paraffin'(50-60'deg)'
- solidifies'section'rapidly'
6) Embedding'
- paraffin'solidified'into'plastic'mold'block'with'tissue'embedded'
7) Sectioning'
- tissues'won’t'fall'off'since'paraffin'has'gone'into'deep'spaces'in'tissues'
- done'on'precision'machine:'microtome'
- may'cause'wrinkles/tears'
'
8) Water'bath'&'spreading'
- wrinkles'straightened'by'floating'sections'on'warm'water'bath'(temp'not'hot'
enough'to'melt'paraffin)''
- slides'spread'out'to'be'dried'
9) Staining'
- haematoxylin'='basic'dye'='stain'acidic'='blue'='basophilic'
- eosin'='acidic'dye'='stain'basic'='pink'='acidophilic''
'
'
'
'
'
'
'
Document Summary
Preparation of histological sections: collection of tissue, fixation. Preserves tissue, stops decomposition & autolysis: dehydration. = tissues may shrink removes water immerse tissue in increasing strength of ethyl alcohol: clearing replace alcohol with paraffin solvent (carcinogenic) Eg of paraffin solvent: toluene, benzene, xylene removes fat: infiltration. Dip tissue in molten paraffin (50-60 deg) solidifies section rapidly: embedding. Paraffin solidified into plastic mold block with tissue embedded: sectioning tissues won"t fall off since paraffin has gone into deep spaces in tissues. May cause wrinkles/tears: water bath & spreading. Wrinkles straightened by floating sections on warm water bath (temp not hot enough to melt paraffin) slides spread out to be dried: staining. Haematoxylin = basic dye = stain acidic = blue = basophilic. Eosin = acidic dye = stain basic = pink = acidophilic: haematoxylin stains, nucleus, ribosomes (gives cytoplasm bluish tint, eosin stains, cytoplasm (sometimes washed out, collagen, connective tissues, csm stain not visible.
