Introduction to Tissue Processing Flashcards
- a better & more effective means of studying tissues whether normal or abnormal is by examination of their sections & smears which have been permanently preserved, stained & mounted on glass slides with cover slips for permanent keeping.
Processing of Tissue
Why examine histopathologic specimens?
• Pathology attempts to explain the whys and wherefores of the signs and symptoms manifested by patients while providing a sound foundation for rational clinical care and therapy.
• Determine if the sample is benign or malignant.
Methods of tissue examination
2.1. Fresh tissue
2.2. Preserved tissue
are usually examined when there is an immediate need for evaluation
Fresh Tissues
Advantages of fresh tissue
Examined in the living state thereby allowing protoplasmic activities such as: motion, mitosis, phagocytosis and pinocytosis to be observed.
Disadvantage of fresh tissue
o Its use has been limited
o Liable to develop the changes that have usually been observed after death.
Methods of Fresh Tissue Examination
- Teasing or Dissociation
- Squash preparation (Crushing)
- Smear Preparation
Streaking
Spreading
Pull apart
Touch Preparation ( Impression smear) - Frozen section
• A process whereby a selected tissue specimen is immersed in a watch glass containing ___, carefully dissected or separated, and examined under a microscope.
• Unstained by _, ,
Teasing or Dissociation
- isotonic salt solution
- Phase Contrast or Bright Field Microscopy, or stained with differential dyes
• A process whereby small pieces of tissue not more than _ in diameter are placed in a microscopic slide and forcibly compressed with another slide or with a cover glass
• A __ may be placed at the junction of the slide and the cover glass, and allowed to be absorbed by the tissue through _
Squash preparation (Crushing)
- 1 mm
- vital stain
- capillary attraction
• The process of examining sections or sediments whereby cellular materials are spread lightly over a slide by means of a _ or _ , or by making an _ with another slide
• Especially useful in _ , particularly for _
Smear Preparation
- wire loop or applicator
- apposition smear
- cytologic examinations
- cancer diagnosis
▪ With an applicator stick or platinum loop, the material is rapidly and gently applied in a _ throughout the slide.
▪ Attempts to obtain a __
▪ _ have to be avoided, since they make the tissues unsuitable for examination
Streaking
- direct or zigzag line
- relatively uniform distribution of secretion
- Too thin or too thick smears
o A selected portion of the material is transferred to a clean slide and gently spread into a moderately thick film by teasing the _ apart with an applicator stick
o A little more tedious than streaking but maintains _ of the material to be examined
o For ,,_
Spreading
- mucous strands
- cellular interrelationships
- fresh sputum, bronchial aspirates, and thick mucoid secretions
o Done by placing a _ upon one slide and facing it to another clean slide
o Material disperses evenly over the surface of the two slides
o Slight movement of the 2 slides in opposite directions may be necessary to initiate the flow of materials
o 2 slides are then pulled apart in a single uninterrupted motion
Pull-apart
- drop of secretion or sediment
o A special method of smear prep whereby the surface of a freshly cut piece of tissue is brought into contact and pressed on to the surface of a clean glass slide, allowing the cells to be transferred directly to the slide for examination by _ or _
o Cells may be examined without destroying their _
Touch preparation (Impression smear)
- Phase Contrast microscopy or stained for light microscopic study
- actual intercellular relationship
• Normally utilized when a rapid diagnosis of the tissue in question is required, and is especially recommended when _ and _ are to be demonstrated
o Very thin slices, around _ in thickness are cut from a fresh tissue frozen on a _, a cold chamber kept at an atmospheric temperature of _
Frozen section
- lipids and nervous tissue elements
- 10-15μ
- Cryostat
- -10oc to -20oC
Frozen sections are commonly used for:
o Rapid pathologic diagnosis during surgery
o Diagnostic and research enzyme histochemistry
o Diagnostic and research demonstration of soluble such as lipids and carbohydrates
o Immunofluorescent and immunohistochemical staining
o Some specialized silver stains, particularly in neuropathology.
Commonly used methods of freezing:
o Liquid nitrogen
o Isopentane cooled by liquid nitrogen
o Carbon dioxide gas
o Aerosol sprays
Solid structures and tissues must be preserved and carefully processed in the following order:
Preserved tissue
1. Fixation
Decalcification (Optional)
2. Dehydration
3. Clearing
4. Infiltration (Impregnation)
5. Embedding
6. Trimming
7. Section-Cutting
8. Staining
9. Mounting
10. Labeling
Receiving, custody and identification of tissues
Receipt of Specimens
A. Specimens can be received fresh (without fixative) or in formalin.
B Specimen Accessioning
a. For _ tissue is received fresh for immediate microscopic evaluation by the Pathologist.
b. May be received for an _
Fresh
- frozen sections
- OR consultation
The Pathologist will look at the specimen and make a gross diagnosis.
c. As the PA, _ .
d. As the PA, _, if necessary; however,
always check with the Pathologist before making any of these decisions.
- you may weigh and measure the specimen
- you may also ink the specimen
In Formalin
a. Proceed as a _
b. Ideally, the specimen should have __
routine surgical specimen
at least 20 x its volume of
formalin
A. Each specimen receives an .
B. Each number is unique to that particular case and is NEVER reused. C. The ,, are labeled with the case/asssession number.
Specimen Accessioning
- accession number
- specimen container(s), the requisition slip and all cassettes
, often referred to as “cut-up”, it involves a careful examination and description of the specimen its - ,,_
Grossing
- appearance, - number of pieces and dimensions
