Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Histopath Readings - Chapter 6(Midterms) > Part 1 > Flashcards

Part 1 Flashcards

1
Q

The first and most critical step in histotechnology is

A

Fixation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

A process that preserves tissues from decay, thereby preventing autolysis or putrefaction.

A

Fixation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

If fixation is not adequate, these other processes that follow will be affected

A

Dehydration, Clearing, infilatration, Embedding, Microtomy and Staining

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

T/F: Fixation should be carried out as soon as possible after removal of the tissues (in the case of surgical pathology) or soon after death (in the case of autopsy) to prevent autolysis.

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

This stabilize the fine structure, both inside and between cells, by making macromolecules resistant to dissolution by water and other liquids

A

Lysosomal enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Primary goal of fixation

A

Preserve the morphologic and chemical integrity of the cell in as life-like a manner as possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

T/F: All vital cellular processes stop when the tissue is placed in a fixative.

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Second goal of fixation

A

To harden and protect the tissue from the trauma of further handling, so that it is easier to cut and process for microscopy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Results from tissue digestion by intracellular enzymes that are released when organelle membranes rupture.

A

Autolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

brought about by microorganisms which may already be present in the specimen.

A

Bacterial Decomposition or putrefaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Processes that must be prevented in fixation

A

Autolysis and putrefaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Fixation in __ will initially cause slight swelling of tissue specimen

A

10% buffered formalin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Specimen may shrink or lose how many percent during processing?

A

20-30% of its volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

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

A

Swell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Leaving the tissue in a strong salt (hypertonic sol’n) will cause the cell to

A

Shrink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Cell structure also called as “suicide sac” that contains hydrolytic enzymes that are released when the integrity of the cell is destroyed

A

Lysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

occurs due to the action of these hydrolytic enzymes

A

Postmortem decomposition (autolysis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

This method include heating, microwaving and cryo-preservation (freeze drying)

A

Physical Method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

A type of physical method rarely used on tissue specimens, its application being confined to smears of microorganisms

A

Heat fixation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Physical method which can be regarded as a form of heat fixation, is now widely practiced in routine laboratories.

A

Microwave fixation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Physical method usually in the form of freeze drying, has some applications in histochemistry but is not usually applied to diagnostic tissue specimens.

A

Cyropreservation

22
Q

Fixation method that is usually achieved by immersing the specimen in the fixative solution (immersion fixation) or, in the case of small animals or some whole organs such as a lung, by perfusing or injecting the vascular system with fixative (perfusion fixation)

A

Chemical Fixation

23
Q

Can be used to vapor-fix freeze-dried tissues.

A

Paraformaldehyde and osmium tetroxide

24
Q

Mechanism involved in fixation whereby the chemical constituent of the fixative is taken in and becomes part of the tissue by forming cross-links or molecular complexes and giving stability to the protein.

A

Additive fixation

25
Q

Example of additive fixation

A

Formalin, Mercury, Osmium tetroxide

26
Q

Mechanism involved in fixation whereby the fixing agent is not incorporated into the tissue, but alters the tissue composition and stabilizes the tissue by removing the bound water attached to H-bonds of certain groups within the protein molecule.

A

Non-additive fixation

27
Q

Fixative solutions may contain a single fixative agent dissolved in a solvent such as water or alcohol or more commonly __ to stabilize pH

A

Buffer solution

28
Q

counter the shrinkage caused by other agents such as ethanol.

A

Acetic acid

29
Q

Benefits of fixation

A
  • Allows thin sectioning of tissue by hardening tissue
  • Prevents autolysis and inactivates infectious agents (except prion diseases)
  • Improves cell avidity for special stains
30
Q

How many hour specimens should be transferred to fixative?

A

<1 hour after surgery

31
Q

Deterioration will commence with the __

A

Loss of blood supply

32
Q

Tissues should be fixed in a sufficient volume of solution

A

Ratio of 20:1 or at least 10:1 fixative to specimen

33
Q

Fixatives diluted and/or contaminated by bodily fluids (e.g. bile, blood, feces) will be __ in concentration and must be replaced

A

Reduced

34
Q

T/F: Prolonged fixation may be more difficult to reverse and may also result in loss of immunohistochemical antigenicity.

A

TRUE

35
Q

T/F: Pinning specimens to a corkboard or inserting a paper or gauze “wick” into tubular structures CANNOT improve fixation and reduce tissue distortion.

A

FALSE; Pinning spx CAN improve fixation

36
Q

The amount of fixative used has been __ times the volume of tissue to be fixed

A

10-20x

37
Q

This also enhance fixation of the specimen.

A

Agitation

38
Q

The most common error in histotechnology is __

A

ratio of tissue volume to fixative volume

39
Q

Fixation is best carried out close to neutral pH, in the range of

A

6-8

40
Q

Favors formation of formalin-heme pigment that appears as black, polarizable deposits in tissue.

A

Acidity

41
Q

Common buffers include

A

phosphate, bicarbonate, cacodylate and veronal

42
Q

Commercial formalin is buffered with phosphate at what pH

A

7

43
Q

Temperature for regular tissue processing

A

40degC

44
Q

Temperature for electron microscopy and some histochemistry, the ideal temperature is

A

0-4degC

45
Q

Cell that are best fixed at room temp even for electron microscopy

A

Mast cells

46
Q

Is used to slow down decomposition if the tissue needs to be photographed and cannot be fixed immediately.

A

Refrigeration

47
Q

Continues to undergo mitosis (growth) up to 30 minutes after death when refrigerated.

A

Bone marrow

48
Q

The use of __ for fixation in bacteriology and for blood films is well known.

A

Heat

49
Q

Formalin heated to __ is sometimes used for the rapid fixation of very urgent biopsy specimens, although the risk of tissue distortion is increased.

A

60degC

50
Q

T/F: An increase in temperature can increase the rate of fixation but can also increase the rate of autolysis

A

TRUE

Histopath Readings - Chapter 6(Midterms) (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions