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Histopathology > Examination of Fresh Tissue and Fixation > Flashcards

Examination of Fresh Tissue and Fixation Flashcards

1
Q

The microscopic study of the normal tissues of the body

A

Histology

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2
Q

The microscopic study of tissues affected by disease

A

Histopathology

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3
Q

The simplest, least invasive test and uses the smallest needle to simply remove cells from the area of abnormality.

A

Fine needle aspiration

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4
Q

This is not always adequate to obtain a diagnosis, depending on the area being biopsied

A

Fine needle aspiration

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5
Q

Removes not only cells, but also a small portion of the surrounding tissue. This provides additional information to assist in the examination of the lesion.

A

Core needle biopsy

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6
Q

Takes out even more surrounding tissues. It takes some out of the abnormality, but noy all. The doctor will slice into the lesion and remove only a portion of it. If the lesion is found to be cancerous, further surgery may be needed to remove the lesion.

A

Incisional biopsy

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7
Q

Generally removes the entire area in question

A

Excisional biopsy

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8
Q

Considered to be the primary technique for obtaining diagnostic full-thickness skin specimens

A

Punch biopsy

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9
Q

The technique involves the use of a circular blade that is roated down through the epidermis and dermis, and into the subcutaneous fat, yielding a 3-4 mm cylindrical core of the tissue sample.

A

Punch biopsy

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10
Q

Where small fragments of tissue are shaved from a surface (usually a skin)

A

Shave biopsy

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11
Q

Where tissue is scooped or spooned to remove tissue or growth from body cavity such as endometrium or cervical canal

A

Curettings

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12
Q

specimens that are usually examined when there is an immediate need for evaluation

A

Fresh tissues

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13
Q

Is a process whereby a selected tissue specimen is immersed in isotonic salt solution such as normal saline solution or roger’s solution in a petri dish or watch glass, carefully dissected with a needle and separated by direct or zigzag spread using an applicator stick.

A

Teasing or or dissociation

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14
Q

In teasing or dissociation, the specimen is either stained with _____ or examined unstained by _______

A

supravital
phase-contrast microscopy

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15
Q

Is a process whereby small pieces of tissue (not more than one mm in diameter) are placed in a microscopic slide and forcibly compressed with another slide or with a cover glass.

A

Squash preparation (Crushing)

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16
Q

In squash preparation (crushing), a supravital stain if necessary, may be placed at the junction of the slide and the cover glass, and allowed to be absorbed by the tissue through _____

A

capillary attraction

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17
Q

the method of preparing the smears differs depending on the nature of the material to be examined.

A

Smear preparation

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18
Q

These may be examined as either as fresh prep similar to that described for teased preparations, or by using a supravital technique.

A

Smear

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19
Q

This is useful for preparing smears of thick secretions like mucous fluids, serous fluids, sputum, enzymatic lavage samples from GI tract, and blood smears

A

Smear preparation

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19
Q

This is useful for preparing smears of thick secretions like mucous fluids, serous fluids, sputum, enzymatic lavage samples from GI tract, and blood smears

A

Smear preparation

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20
Q

With an applicator stick or an platinum loop, the material is rapidly and gently applied in a direct or zigzag line throughout the slide, attempting to obtain a relatively uniform distribution.

A

Streaking

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21
Q

A selected portion of the material is transferred into a clean slide and gently spread into moderately thick film by teasing the mucous strands with applicator stick.

A

Spreading

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22
Q

It is little more tedious than streaking, but has many advantage of maintaining cellular interrelationships of the material to be examined

A

Spreading

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23
Q

It is specially recommended for smear preparation of fresh sputum and bronchial aspirates, and also for thick mucoid secretions

A

Spreading

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24
Q

This is done by placing a drop of secretion or sediment upon one slide and facing it unto another clean side.

A

Pull-apart

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25
Q

This is a special method of smear preparation whereby the surface of a freshly cut pieces of tissue is brought into contact and pressed on the surface of a clean glass slide, allowing the cells to be transferred directly to the slide for examination phase-contrast microscopy or staining for light microscopic study.

A

Touch preparation (Impression smear)

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26
Q

A fresh tissue is frozen on a ______ with ____

A

microtome with CO2

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27
Q

A cold chamber kept at an atmospheric temperature of ______.

A

Cryostat
-10C to -20C

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28
Q

Commonly used methods of freezing include:

A
  1. Liquid nitrogen
  2. Isopentane cooled by liquid nitrogen
  3. Carbon dioxide gas
  4. Aerosol sprays
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29
Q

Freezing agent generally used in histochemistry and during intra-operative procedures.

A

Liquid nitrogen

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30
Q

The most rapid of the commonly available freezing agents.

A

Liquid nitrogen

31
Q

The main disadvantage of a liquid nitrogen is that soft tissues are liable to crack due to rapid expansion of ice within the tissue, producing ______

A

ice crystals or freeze artifacts

32
Q

_______ is liquid at room temperature

A

Isopentane

33
Q

Tissue blocks can also be frozen by adapting a conventional freezing microtome gas supply of _______ from a ______

A

Carbon dioxide gas
CO2 cylinder

34
Q

The use of this has become increasingly popular in recent years, and is adequate for freezing small pieces of tissue except muscle.

A

Aerosol sprays

35
Q

Quick-freezing spray cans of _____ have a distinct advantage of rapidly freezing blocks of any type of tissue

A

Fluorinated hydrocarbons (Cryokwik)

36
Q

Is a refrigerated apparatus used for fresh tissue microtomy

A

Cryostat or Cold Microtome

37
Q

Cryostat consists of microtome (rotary microtome) kept inside a cold chamber w/c maintains the temperature between _______ by an adjustable thermostat

A

-10 to 1-30C (ave. -20C)

38
Q

Majority of the sections in cryostat can be cut in _____, where the temperature for sectioning can be accurately established and controlled.

A

Isothermic situations

39
Q

Capable of freezing fresh tissues within 2-3 minutes

A

Thermostat

40
Q

Cutting sections of Crytostat

A

4 micra

41
Q

Provides sections for fresh tissue examination esp. Fluorescent Antibody Staining techniques or Histochemical enzyme studies

A

Cryostat or Cold Microtome

42
Q

It is the first and most critical step in the histopathology

A

Fixation

43
Q

Primary aim of fixation

A

Preserve the morphology and chemical integrity of the cell

44
Q

fixation must preserve:

A

shape
structure
intercellular relationship
chemical constituents

45
Q

fixation must prevent:

A

degeneration
decomposition
putrefaction
distortion of tissues

46
Q

Leaving the tissue specimen in ____ will cause to dry out and result to distortion

A

Air

47
Q

Leaving the tissue in water (hypotonic solution) will cause the cell to _____

A

swell

48
Q

Strong salt (_____) will cause the cell to ____.

A

Hypertonic solution
shrink

49
Q

2 mechanisms in fixation:

A
  1. Additive fixation
  2. Non-additive fixation
50
Q

Mechanism of fixation where chemical constituents are taken in and become part of the tissue. It form cross-links and stabilize protein

A

Additive fixation

51
Q

Mechanism of fixation where the fixing agent is not incorporated into the tissue. Removing of water to form new cross-links

A

Non-additive fixation

52
Q

Main factors involved in fixation:

A
  1. Hydrogen-Ion Concentration
  2. Temperature
  3. Thickness of section
  4. Osmolality
  5. Concentration
  6. Duration of fixation
53
Q

Fixation is best carried at pH ____

A

pH 6-8

54
Q

Surgical specimens must be at _______

A

room temperature (20-25C)

55
Q

Tissue processors must be maintained at ____

A

40C

56
Q

Electron microscopy must be at ______

A

0-4C

57
Q

Formalin at 60C is used for _____

A

urgent biopsy specimens

58
Q

Formalin at 100C is used to ____

A

fix tissues with tuberculosis

59
Q

High temperature –> ____ Distortion

A

Higher

60
Q

Thickness of section for electron microscopy

A

1-2 mm2

61
Q

Thickness of section of light microscopy

A

2 cm2

62
Q

Thickness of section for light microscopy (thin sections)

A

0.4 cm

63
Q

Brain tissue is fixed using _____ for 2-3 weeks for easier cutting of sections

A

10% Formalin

64
Q

Hypertonic solution may lead to _____

A

shrinkage

65
Q

_______ may lead to swelling and subsequent poor fixation

A

Hypotonic and Isotonic solution

66
Q

Osmolality normal val:

A

400-450 mOsm

67
Q

Osmolality of Isotonic solutions

A

340 mOsm

68
Q

Recommended/Best Osmolality

A

Slightly Hypertonic solutions

69
Q

Most common fixative:

A

10% neutral buffer formalin

70
Q

Fixing agent used in electron microscopy

A

3% Glutaraldehyde

71
Q

Fixing agent used in Immunoelectron microscopy

A

0.25% Glutaraldehyde

72
Q

Presence of this causes polymerization of the aldehyde –> decreased effectiveness

A

BUFFER

73
Q

Recommended time for primary fixation in buffered formalin from the time the specimen is obtained

A

2-6 hours

74
Q

Recommended time in electron microscopy for duration of fixation

A

3 hours

75
Q

Average penetration:

A

1 mm/hour

Histopathology (5 decks)

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