What is the purpose of tissue processing?

1. DEFINITION : Tissue processing: The aim of tissue processing is to embed the tissue in a solid medium firm enough to support the tissue and give it sufficient rigidity to enable thin sections to be cut, and yet soft enough not to damage the knife or tissue.

What is the main principle of tissue processing?

Principles of tissue processing. Tissue processing is designed to remove all extractable water from the tissue, replacing it with a support medium that provides sufficient rigidity to enable sectioning of the tissue without parenchymal damage or distortion.

What is tissue processing?

Tissue processing is the technique by which fixed tissues are made suitable for embedding within a supportive medium such as paraffin, and consists of three sequential steps: dehydration, clearing, and infiltration.

What is the need for purpose of processing a tissue for histological studies?

Tissues from the body taken for diagnosis of disease processes must be processed in the histology laboratory to produce microscopic slides that are viewed under the microscope by pathologists.

What happens in tissue processing?

“Tissue processing” describes the steps required to take an animal or human tissue from fixation to the state where it is completely infiltrated with a suitable histological wax and can be embedded ready for section cutting on the microtome.

What is the first step of tissue processing?


The first stage in tissue processing is dehydration (the removal of water). In tissues, water is present in both free and bound forms and needs to be removed before processing can continue.

What are the types of tissue processing?

There are three main steps in tissue processing, namely: ‘dehydration’, ‘clearing’, and ‘infiltration’. Each of the steps of the processing method involves the diffusion of a solution into tissue and dispersion of the previous solution in the series.

Who discovered tissue processing?

From Body to Block – A Brief History of Tissue Processing. Since the word ’tissue’ was defined in the late 1700s by Marie Francois Bichat, the father of histology, the advances that have been made in the world of cellular pathology are beyond measure.

What is the most important step in tissue embedding?

Correct orientation of tissue in a mould is the most important step in embedding. Incorrect placement of tissues may result in diagnostically important tissue elements being missed or damaged during microtomy.

Why dehydration of tissue is important?

Dehydration of tissues is the important process because of the paraffin, in which the tissues are embedded, is not miscible with water and does not penetrate the tissue effectively. Hence water in the tissue should be removed before embedding; this process is called as dehydration.

What is the most common processing problem?

The most common problems in processing are caused by processing both biopsy and large tissue specimens simultaneously on the same processing program. This leads to overprocessing and excessive dehydration of the biopsy tissues and/or underprocessing and incom- plete dehydration of the larger specimens.

What is dehydration in tissue processing?

Dehydration is the process of removing water from tissues and time required. depends on permeability of tissues, temperature, vacuum applied and continuous rotation of fluid to prevent stagnation of fluid around tissues. ● Most commonly used dehydrant is ethyl alcohol. ●

What is the purpose of xylene in tissue processing?

Xylene is a chemical commonly used in the histology lab as a clearing agent. Clearing agents are used to make the slides easier to read, by making the tissue transparent, or clear. Clearing is a step that occurs during tissue processing, after water has been removed from a tissue.

What is the purpose of clearing the tissue specimen?

Clearing is important for removing alcohols and permitting tissue infiltration with paraffin wax. Others have investigated alternative clearing agents that preserve morphology and staining characteristics of tissue sections while reducing cost.

What is the purpose of a fixative?

The primary function of fixatives is to prevent autolysis (enzymes attack) as well as putrefaction (bacterial attack) of tissues.

What is toluene used for?

Toluene is found naturally in crude oil, and is used in oil refining and the manufacturing of paints, lacquers, explosives (TNT) and glues. In homes, toluene may be found in paint thinners, paintbrush cleaners, nail polish, glues, inks and stain removers.

What is benzene used for?

It ranks in the top 20 chemicals for production volume. Some industries use benzene to make other chemicals that are used to make plastics, resins, and nylon and synthetic fibers. Benzene is also used to make some types of lubricants, rubbers, dyes, detergents, drugs, and pesticides.

What is phenol used in?

Phenol is used primarily in the production of phenolic resins and in the manufacture of nylon and other synthetic fibers. It is also used in slimicides (chemicals that kill bacteria and fungi in slimes), as a disinfectant and antiseptic, and in medicinal preparations such as mouthwash and sore throat lozenges.

What is methanol used for?

Methanol — the simplest alcohol (CH3OH) — is a chemical building block for hundreds of everyday products, including plastics, paints, car parts and construction materials. Methanol also is a clean energy resource used to fuel cars, trucks, buses, ships, fuel cells, boilers and cook stoves.

What is the pH of methanol?

In methanol, neutral is when H equals CH3O , which occurs when H is 10 8.3 or a pH of 8.3. Methanol–water mixtures have autoprotolysis constants between 14 (water) and 16.6 (methanol), so neutral in these mixtures ranges from pH 7 to pH 8.3.

What is ethanol used?

Ethanol is an important industrial chemical; it is used as a solvent, in the synthesis of other organic chemicals, and as an additive to automotive gasoline (forming a mixture known as a gasohol). Ethanol is also the intoxicating ingredient of many alcoholic beverages such as beer, wine, and distilled spirits.

Does methanol dissolve plastic?

Chloroform/methanol will dissolve most plastics.

Can you pour ethanol down the sink?

ETHANOL CANNOT BE DISPOSED OF DOWN THE DRAIN AT ANY CONCENTRATION. It must be collected and disposed of as hazardous waste.

Can I dump methanol?

Disposal: Waste methanol must never be discharged directly into sewers or surface waters. Large quantities of waste methanol can either be disposed of at licensed waste solvent disposal company or reclaimed by filtration and distillation. It can also be incinerated.