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MT6321 > [LEC] UNIT 7 SECTIONING > Flashcards

[LEC] UNIT 7 SECTIONING Flashcards

1
Q

Process whereby tissues are cut into uniformly thin slices or “sections” w/ the aid of a machine to facilitate the studies under the microscope

A

Sectioning/Microtomy

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2
Q

Important device in microscopy

A

Microtome

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3
Q

Sectioning instrument that allows for the cutting of extremely thin slices of material called sections.

A

Microtome

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4
Q

Transparency of the tissue in the microscope is affected by 2 factors:

A
  • how good sectioning is
  • how good the clearing agent is
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5
Q

thin slices of tissue (4-15μ) thick

A

Sections

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6
Q

WHat are the general types of tissue sections?

A

Paraffin section
Celloidin section
Frozen section

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7
Q

What type of tissue section uses rocking and rotary microtomes?

A

Paraffin sections

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8
Q

What type of tissue section uses a sliding microtome

A

Celloidin section

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9
Q

cut from tissues that have been fixed and frozen w/ CO2 or for fresh or fixed tissues frozen w/ the cryostat

A

Frozen sections

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10
Q

The bone should be decalcified with _____?

A

EDTA (decalcifying agent)

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11
Q

T/F: In frozen section, fixation and embedding are happening at the same time

A

True

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12
Q

Unit of measurement for the thickness of sections

A

Micron (μ)

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13
Q

1/1000th of a millimeter / (1/25 000th of an inch)

A

Micron (µ)

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14
Q

Use steel, glass, or diamond blades depending upon the specimen being sliced and the desired thickness of the section being cut

A

Microtome knives

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15
Q

Materials of microtome knives are usually made of?

A

■ Standard Steel blades / Disposable steel blades (most common)
■ Glass knife (for electron microscopy; sophisticated tissue processing)
■ Industrial grade diamond knife

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16
Q

Microtome knife for electron microscopy?

A

Glass knife

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17
Q

Most common microtome knife?

A

Standard Steel blades / Disposable steel blades

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18
Q

Wax is REMOVED with a sharp knife (cutter knife / kitchen knife) until about 4-60 mm remains on all sides of the tissue (depending on the tissue)

A

Block Trimming

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19
Q

T/F: ONLY small flakes of wax should be trimmed at a time

A

TRUE

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20
Q

done at approximately 30 mm at a time until tissue SURFACE IS EXPOSED

A

Coarse Trimming/Facing

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21
Q

set thickness adjuster at 15 mm or advancing the block using the coarse feed mechanism

A

Fine Trimming

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22
Q

surface block is trimmed away until the entire tissue surface has been partly exposed

A

Fine Trimming

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23
Q

Biconcave, Plano- concave, Wedge, Chisel-shaped

What are these?

A

Microtome knife profiles

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24
Q

Action of sharpening a knife by grinding cutting edge, either on a stone or with an abrasive compound

A

Honing

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25
Process of polishing the cutting edge of the knife on leather or canvas
Stropping
26
The straight line formed by intersection of 2 planes, the cutting facets
Cutting edge
27
the ribbons produced are returned by the pathologist due to presence of ridges, lines and scratches, but this is solved by _________?
adjusting the angles in the microtome
28
AKA Facet angle, Cutting angle
Bevel Angle
29
What type of knife angle is this? 27° to 32°
bevel angle
30
What type of knife angle is this? 15°
wedge angle
31
What type of knife angle is this? 5° to 10°
clearance angle
32
What type of knife angle is this? Opposite of the clearance angle
Rake angle
33
The lower the angle, the ________ the section
the thinner
34
higher the angle, the tissue is more _________ with its pointy motion
scraped
35
Positive angle or Negative angle? results in cutting action
positive angle
36
Positive angle or Negative angle? results in scraping action
negative angle
37
What knife angle is this? Angle formed between the CUTTING EDGE (PLANES) of the microtome
Bevel Angle
38
T/F: The BIGGER the bevel angle, the sharper the knife.
F. The smaller.
39
T/F: Too small bevel angle permits elastic distortion of the edge
T.
40
What is the recommended width of the two facets on the cutting edge of the knife?
0.1 to about 0.6mm (this is under bevel angle na bullet :D)
41
What knife angle is this? The angle between the sides of the knives
Wedge
42
What knife angle is this? Angle formed between the surface of the block and the cutting facet of the knife
Clearance angle
43
What knife angle is this? Ensures only the cutting edge of the knife touches the specimen block
Clearance angle
44
T/F: Too much clearance causes knife chatter
T
45
What knife angle is this? Angle between upper surface of the cutting facet and the surface of the block
Rake Angle
46
The __________ angle prevents contact between the knife facet and the face of the block a. rake b. bevel c. clearance d. wedge
c. clearance
47
T/F: The angle of the knife can be adjusted in the microtome, same with the cutting face
T.
48
blade passes through the mucosa last a. skin b. intestine c. cervix
b. intestine
49
blade passes through the epidermis last a. skin b. intestine c. cervix
a. skin
50
present a point of dense tissue to the blade rather than a straight edge a. skin b. intestine c. cervix
c. cervix
51
What knife profile is this? (Profile A-D) Plano concave
Profile B
52
What knife profile is this? (Profile A-D) Plane shaped
Profile D
53
What knife profile is this? (Profile A-D) Wedge shaped
Profile C
54
What knife profile is this? (Profile A-D) Strongly plano concave/biconcave
Profile A
55
What knife design and cut types? Extremely sharp, but are also very delicate and are therefore only used with soft samples.
Planar Concave
56
What knife design and cut types? With its blunt edge, raises the stability of the knife, whilst requiring significantly more force to achieve the cut
Chisel Profile
57
What knife design and cut types? More stable and fine use in moderately hard materials, such as in epoxy or cryogenic sample cutting
Wedge Profile Knives
58
T/F: Profiles C and D produces the sharpest edge
F. Profiles A and B
59
used on sliding, rotary, and rocking microtomes
Profile A: Plano-concave knife profile
60
Lesser concavity is for what section?
for celloidin sections
61
More concave is for what section?
for parafiin sections
62
T/F: using a plano concave knife in a rotary microtome can form ribbons
F. It cannot form ribbons
63
What knife profile is this? - less rigid - prone to vibration - classify knife shape with concavity on both sides
Profile B: Biconcave knife profile
64
What knife profile is this? recommended for cutting paraffin embedded section on a rotary microtome
Profile B: Biconcave knife profile
65
Profile B: Biconcave knife profile is introduced by H________?
Heifflor
66
T/F: Profile B: Biconcave knife profile is used for celloidin
F. Not for celloidin, ideally for softer embedding media
67
What knife profile is this? Used in all types of microtomes to cut all types of tissues (i.e. freezing, rotary, and rocking microtomes
Profile C: Wedge knife profile
68
What knife profile is this? - Both cutting surfaces are plane or flat - Known as the standard knife profile - More rigid knife than Profiles A and B
Profile C: Wedge knife profile
69
What knife profile is this? Most commonly utilized steel knife for routine histopathology
Profile C: Wedge knife profile
70
What knife profile is this? Used for sectioning FFPE tissues
Profile C: Wedge knife profile
71
Yes/No: In troubleshooting thick sections, you adjust the thickness and increase the clearance angle.
No - Clearance angle is lowered
72
What causes defect in blade egde, calcium, bone or hard material in the specimen?
Vertical Scratches
73
T/F: Vertical scratches are usually caused by knife havings NICKS.
True
74
T/F: Vertical scratches are usually caused by knife havings NICKS.
True
75
What are the causes of holes in a tissue section?
1. Blocked is faced too aggressively 2. Specimen is excessively dehydrated or improperly processed
76
How to prevent holes in tissue section?
Chill the block with ice before cutting & discard ribbons untile hole disappear
77
This commonly occurs in very hard tissues like uterus
Washboarding or Undulation
78
In washboarding or undulation in tissue section there is presence of _______ lines?
Horizontol ("Blinds")
79
Blinds are caused by too high or too low clearance angle?
Too HIGH
80
How to prevent Washboarding or Undulation?
Proper clamping of blade and block Ensure the block holder shaft is not over extended Ensure the microtome is in good working order Decrease the blade tilt
81
Occur when block holder is not paraller to the blade or "Slanted"
Block face Unevenly Sectioned
82
T/F: In preventing Block face, ensure at the end of sectioning, block holder is adjusted, so that block face & blade are perfectly parallel.
False — At the beginning of sectioning
83
This results when lower block edge is not parallel to the knife edge
Crooked Ribbons
84
Failure of ribbon to form is commonly caused by?
Dull blade
85
What to do if ribbons doesn't form?
Paraffin with lower melting point Decrease blade tilt Change room temp
86
This promotes adhesion of sections
Adhesives
87
Adhesives should be spread _______ and ______ on a clean _______ slide.
Thinly; Evenly; Grease-free
88
After spreading it on the slides, it will be gently approximated to the end of the ribbon, and drawn ______ in a near _____ motion.
Upwards; Vertical
89
T/F: In floatation water bath, tissue ribbons are fished and should not attach to the slide
False - should attach to the slide!!!!!
90
Adhesive is applied to the _____ for the ribbons to attach
Slide
91
Yes/No: Will sections float when submitted to strong alkali solution during staining.
Yes!!!
92
What type of tissue adhesive? Background staining may be detected due to uptake of dyes
Albumin
93
T/F: In Albumin, preservative should not be added to prevent putrefaction
False — Should be added!!!!!!
94
Children, What is Putrefaction?
Decomposition of proteins
95
In Albumin, this is also added to increase viscosity and prevent complete drying
Glycerol
96
What are the different sources of Albumin?
Egg Albumin Bovine Human Albumin (plasma)
97
T/F: In albumin, it is more effective if drying of sections takes place above the coagulation point.
TREEEWWWWW
98
What is the commercially prepared Albumin?
Meyer's Egg Albumin

MT6321 (3 decks)

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