Removal of fixative and intracellular and extracellular water fron the specimen

Filling cavities of the tissue with paraffin

Replacement of fixative and water with dehydrating agent in preparation for

The most affected step

Dehydrating agent

Alcohol prevent

Accelerated increase in alcohol may result the tissue to

Dehydration involves slow substitution of the water in the tissue with an

Characteristics of an ideal dehydrating solution

Minimum fixative volume

Acetone can be used in long time t/f

Do not dry out the tissues t/f

may be used as long as it does not damage the proteins and miscible,to the fluids to be used subsequently

Signs of water content

+ in anhydrous copper sulfate

Temperature in dehydration

More delicate tissue (embryo) begins at__ ethanol

Typical dehydration sequence (4mm) ethanol/min

Orientation of the tissue must be

Embryo mold must not be in

Best dehydrating agent, Recommended for routine dehydration

Ethanol advs excwpt for routine dehydration

Ethanol may react with

Long use of ethanol may cause

Ethanol extracts more lipids than

Ethanol extractss _ and other_from section

Ethanol is only slightly miscible to

Can be used in Blood, touch preparations and smear preparation but it is toxic

Used in plant and animal micro-techniques, Less shrinkage and distortion than ethanol

Recommended for tissues which do not require rapid processing , Miscible with paraffin

Give 2 butanol cons

Butanol temp

Odorous reag you must use?

Universal solvent-acts as dehydrating and clearing agent

Tertiary butanol mixes well with

Temp where tertiary butanol solidifys

Temp of Tertiary butanol

Excellent substitute for ethanol, Less shrinkage and hardening than ethanol. It is also sufficiently water-free to use in place of absolute ethanol and Less expensive. Used in Microwave processing

Isopropanol Cannot be used in the celloidin technic since _ is insoluble in it

Miscible with 90% alcohol, toluene and xylene Dissolves paraffin wax

Cons of amyl alcohol

Cheap, rapid • Does not extract methylene blue and other dyes from stained sections . May cause less shrinkage of specimen than ethanol

Not reactive with Os0, remaining in specimen. • Miscible with most embedding resins.

Acetone 2 cons

Acetone may induced_in prolonged immersion

Best processing requires a graded series of a mixture of _ and _ before one can go into paraffin

Acetone is a

Universal solvent--it dehydrates and clears. Does not harm tissue over long time periods and Faster dehydrant than ethanol

2 cons of Dioxane

Explosive products in dioxane wgen reused

This where the tisue rriboon palced to fix its fold

2 methods in dioxane

tissue is wrapped in a gauze bag and suspended in a bottle containing dioxane and a little anhydrous calcium oxide

Rapid dehydrating agent • Tissue may remain in it for months without injury

Tissues may be transferred from water or normal saline and stored for months without hardening or distortion • Avoids distortion and does not require graded dilutions

Cellusolve combust at

Universal solvent-it dehydrates and clears • Miscible in all proportions with water, ether chloroform, acetone, and the hydrocarbons xylene, toluene, and benzene

Rapid without excessive shrinkage and hardening; easier cutting of sections • Low toxicity; low fire and explosion

6months exposure to tetrahydrofuran produces

For electron microscopy Dehydrating agent: Transition fluid: Substitute:

softening agent for hard tissues

acts as a softening agent for hard tissues like tendons, nail, dense connective tissues, and keratin masses

_phenol is added to each 95% ethanol stations

This will impair subsequent step