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Histo LEC > Tissue Processing > Flashcards

Tissue Processing Flashcards

1
Q

To study tissues, one must
prepare thin and translucent
histological sections or
tissue slices that can be
studied with the aid of a ______

A

microscope

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2
Q

In order to make a histology
slide, the tissue specimen
undergoes various steps of
_________

A

tissue processing

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3
Q

STEPS IN TISSUE PROCESSING

A
  1. Fixation
  2. Decalcification
  3. Dehydration
  4. Clearing
  5. Infiltration
  6. Embedding
  7. Cutting
  8. Sectioning
  9. Sectioning
  10. Mounting
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4
Q

Since cellular decomposition begins immediately after the death of a human/patient, tissues must be ______ to
prevent alterations in their structure caused by decomposition.

A

fixed

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5
Q

After the specimen is surgically removed from the body, it should be preserved or fixed with a ______ to prevent
the decay of the tissue.

A

fixative

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6
Q
  • Small pieces of tissue are placed in solutions of chemicals that cross-link proteins and inactivate degradative enzymes, which preserve cell and tissue structure.
A

Fixation

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7
Q
  • To preserve tissue structure and prevent degradation by enzymes released from the cells or
    microorganisms, pieces of organs are placed as soon as possible after removal from the body in solutions
    of stabilizing or cross-linking compounds called fixatives.
A

FIXATION

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8
Q

WHY IS FIXATION IMPORTANT?

A
  1. Avoid tissue destruction by digestive enzymes (autolysis) or through bacterial degradation.
  2. Terminate cell metabolism.
  3. Hardens the tissue by cross-linking or denaturing proteins.
  4. Kill pathogenic microorganisms such as bacteria, fungi, and viruses.
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9
Q

Commonly used fixative in fixation

A

Formalin or formaldehyde
37% - 40%

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10
Q

● Only done in specimens such as bone and calcified tissues (and arteries w/ atherosclerosis)

A

DECALCIFICATION

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11
Q

decalcifying agent

A

Nitric acid

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12
Q

Done by successively bathing the specimen in a mixture of ethanol and water from 70% to 100%.

A

Dehydration

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13
Q

In dehydration,_______removes water out of tissue.

A

Alcohol

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14
Q

before infiltration, the fixed tissue must undergo dehydration by having its water
extracted gradually by transfers through a series of increasing ethanol solutions, ending in ________which removes all water.

A

100% ethanol

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15
Q

ASCENDING GRADES OF
ALCOHOL

A

50%
70%
90%
100%

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16
Q

● Removal of the dehydrating agent by immersing the specimen in the solvent that the alcohol and embedding medium is miscible.

A

CLEARING

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17
Q
  • Alcohol is removed in organic solvents in which both alcohol and paraffin are miscible.
A

Clearing

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18
Q

T or F|Clearing agent are highly volatile

A

True - it becomes vapor once exposed to heat

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19
Q

Clearing Agents

A

Xylene and Toluene

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20
Q

Between Xylene and Toluene, which is more commonly used?

A

Xylene

21
Q

After the clearing procedure, the tissue is placed in a melted paraffin
in an oven set at __ -__degree celsius.

A

52-60 degree Celsius

22
Q

The fully cleared tissue is then placed in melted paraffin in an oven at 52°-60°C, which evaporates the clearing solvent and promotes _______ of the tissue with paraffin

A

INFILTRATION

23
Q

WHAT IS USED IN iNFILTRATION?

A

melted paraffin wax

24
Q

is allowing it to harden in a small
container of paraffin at room temperature.

A

Embedding

25
Q
  • makes use of a plastic solution
    which hardens tissue by cross-linking
    polymakers.

○ Eliminates the need to use oven and paraffin; little tissue distortion

A

Plastic resins

26
Q

avoids the higher temperatures needed with paraffin, which helps avoid tissue
distortion.

A

Plastic embedding

27
Q

After the specimen is hardened, it is trimmed into appropriately sized blocks.

○ _____ is removal of excess paraffin.

A

Cutting

28
Q

In sectioning, the block is mounted in microtome and cut with a _______.

A

steel knife

29
Q

Sectioning is done with the aid of _____

A

microtome

30
Q

sections are placed on glass slides and stained for light microscopy or on metal grids for electron-microscopic staining and examination

A

MOUNTING

31
Q
  • Most cells and extracellular material are completely colorless, and to be studied microscopically tissue
    sections must be (dyed).
A

STAINING

32
Q

Application of color to the tissue to highlight structures.

A

Staining

33
Q

Most commonly used
stain:

A

Hematoxylin and Eosin

34
Q

T or F| Hematoxylin and Eosin are insoluble in water

A

FALSE - These dyes are water soluble

35
Q

blue;
basic dye;
usually stains nucleus and RNA-containing portion of cytoplasm.

A

Hematoxylin

36
Q

red;
acidic-dye;
usually cytoplasmic components and collagen.

A

Eosin

37
Q

Tissues with negative charges/acids are readily stained with

A

basic dyes - basophilic

38
Q

Tissues with positive charges are stained with

A

acidic dyes - acidophilic

39
Q
  • stains DNA in the cell nucleus, RNA-rich portions of the cytoplasm, and the matrix of cartilage, producing a dark blue or purple color.
A

Hematoxylin

40
Q
  • stains other cytoplasmic structures and collagen pink.
A

Eosin

41
Q

considered a counterstain, which is usually a single dye applied separately to distinguish additional features of a tissue.

A

Eosin

42
Q

Turnaround time for Standard Routine Tissue Processing

A

5 DAYS

43
Q
  • is a faster but more expensive way to do biopsy however it is by case basis.
A

Frozen Section Biopsy

44
Q

Turnaround time for Frozen Section Biopsy

A

15 MINUTES

45
Q

○ This method is rapid.
○ Routinely done in hospital to study specimens during surgery.

A

Frozen Sections

46
Q

In Frozen Sections, ____ and ____ are best preserved in this method

A

Lipids and Enzymes

47
Q

Fixative agent for frozen section

A

Liquid Nitrogen

48
Q
A

Histo LEC (26 decks)

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