2-MICROTOMY PARAFFIN SECTIONS Flashcards
(128 cards)
1
Q
What is the process of cutting processed tissue into uniformly thin slices for microscopic study
A
microtomy
2
Q
What is the instrument used to cut tissue sections at predetermined thickness
A
microtome
3
Q
What part of the microtome holds the tissue in position
A
block holder
4
Q
What part of the microtome cuts the tissue sections
A
knife carrier and knife
5
Q
What parts of the microtome adjust tissue position and section thickness
A
pawl ratchet feed wheel and adjustment screws
6
Q
What type of microtome cuts serial sections of large paraffin blocks using a rocking motion
A
rocking microtome or rocking Cambridge microtome
7
Q
What type of microtome is most commonly used for routine and research paraffin sectioning with rotary motion
A
rotary microtome
8
Q
What type of microtome cuts celloidin embedded sections and is considered dangerous due to movable exposed knife
A
sliding microtome or base-sledge microtome
9
Q
What microtome is used for cutting unembedded frozen tissue sections rapidly for diagnosis and fat demonstration
A
freezing microtome or cryostat
10
Q
What microtome is kept in a chamber at minus 5 to minus 30 degrees Celsius for freezing fresh tissues and cutting 4 micron sections
A
cryostat or cold microtome
11
Q
What microtome is equipped with glass or gem grade diamond knife to cut ultrathin sections for electron microscopy
A
ultramicrotome
12
Q
What materials are microtome blades made of
A
steel glass diamond
13
Q
What blades are used for cutting soft tissue sections for light microscopy
A
steel blades
14
Q
What blades are ideal for very thin sections for light and electron microscopy
A
glass blades
15
Q
What blades are used for cutting hard materials like bone teeth and hard woods
A
diamond blades
16
Q
What microtome type uses rotary action of handwheel to advance block and cut serial sections
A
rotary microtome
17
Q
What microtome type has block holder on steel carriage moving vertically past fixed knife
A
rotary microtome
18
Q
What microtome type cuts tissues in slightly curved planes and is not preferred for serial sections
A
rocking microtome
19
Q
What microtome type has knife moving back and forth with stationary block and is dangerous
A
sliding microtome
20
Q
What microtome type is used for large brains and whole brain sections
A
base-sledge microtome
21
Q
What microtome type is used for rapid preparation of urgent biopsies and intraoperative diagnosis
A
cryostat
22
Q
What microtomy technique involves cutting sections between 50 nanometers and 100 micrometers thick
A
microtomy
23
Q
What knife has one flat side and one concave side used for cutting celloidin embedded tissues on sliding microtome and paraffin sections on rotary microtome
A
plane concave knife
24
Q
What knife has concave sides on both sides recommended for cutting paraffin embedded sections on rotary microtome
A
biconcave knife
25
What knife has straight sides on both edges used for frozen sections and hard paraffin embedded specimens on base sledge or sliding microtome
plane wedge knife
26
What is the angle formed between the cutting edges of a microtome knife
bevel angle
27
What is the process of removing nicks and irregularities from the knife edge using a sharpening stone
honing
28
What are the types of honing stones used for microtome knives
Belgium yellow Arkansas fine carborundum
29
What is the process of removing burrs formed during honing and polishing the knife edge
stropping
30
What is the purpose of stropping compared to honing
stropping polishes and sharpens while honing removes irregularities
31
What type of blades have replaced conventional steel knives in most laboratories
disposable blades
32
What is the typical thickness of sections cut by disposable blades
2 to 4 microns
33
What equipment maintains water bath temperature 5 to 10 degrees Celsius below paraffin melting point for floating sections
waterbath
34
What is the recommended size and thickness of clean frosted slides for mounting sections
76 by 25 millimeters and 1 to 1.2 millimeters thick
35
What are the three types of rotary microtomes
manual semi automated automated
36
What part of the rotary microtome controls cutting action and section thickness
handwheel and handwheel lock
37
What is the angle between the block face and lower facet of the knife adjustable by knife tilt
clearance angle
38
What clearance angle range is normally set for microtome blades
zero to fifteen degrees
39
What happens if the clearance angle is too slight
tissue sections may be missed or skipped and alternate thick or thin sections occur
40
What is a common problem caused by too slight clearance angle
wrinkled or jammed sections
41
What happens if the clearance angle is too great
chatter or microvibration and washboarding occur
42
What are key factors for perfect microtome section
proper sample preparation environmental conditions tissue orientation skill
43
What are components of proper sample preparation
fixation dehydration clearing embedding
44
What environmental conditions affect microtomy
temperature control humidity control
45
What is important for blade maintenance
avoid touching edge use blade systematically use separate areas for trimming and final cutting
46
What technique improves cutting consistent high quality thin sections
use new blade re chill block face slow uniform cutting stroke do not stop during stroke remove debris with brush
47
What causes lengthwise or vertical scratches lines and splits in sections
dull blades small calcified tissues hard materials bones
48
What causes crooked tissue ribbons and crumbled sections
block edges not parallel to blade blade imperfections block not chilled
49
What causes uneven block face sections
block face not parallel to blade
50
What causes holes in sections
improper processing block faced too aggressively
51
What causes failure to form ribbons
improper processing increase blade tilt room temperature dirty blade
52
What causes lifting of section from blade
too little blade tilt dull blade soft paraffin
53
What causes washboarding or undulations in section
very hard tissues overfixed tissues loose clamping overextended block holder shaft
54
What causes chatter or microscopic vibration in section
hard tissues lack of moisture overfixation overdehydration dull blade fast stroke
55
What causes compressed sections
dull blade too little blade tilt paraffin accumulation fast cutting stroke warm block
56
What is the corrective action for block face unevenly sectioned
re orient tissue block
57
What is the corrective action for washboarding
increase blade tilt
58
What is the corrective action for chatter
increase blade tilt reduce stroke speed
59
What is the corrective action for compressed sections
increase blade tilt use sharp blade slow cutting stroke cool block
60
What is the process of cutting tissues into uniformly thin slices for microscopic study
sectioning
61
What are the three general types of tissue sections
paraffin sections+celloidin sections+frozen sections
62
What type of section uses paraffin embedded tissue blocks cut by rocking or rotary microtome
paraffin sections
63
What type of section uses celloidin embedded tissue cut by sliding microtome
celloidin sections
64
What type of section is cut from tissues fixed and frozen with carbon dioxide or cryostat
frozen sections
65
What is the usual thickness range for paraffin sections
4 to 6 microns
66
What is the recommended knife tilt angle for paraffin sections
zero to fifteen degrees
67
What is the water bath temperature for floating out paraffin sections
45 to 50 degrees Celsius
68
What is the drying oven temperature for mounted sections
2 to 5 degrees Celsius above melting point of paraffin
69
What is the usual thickness range for celloidin sections
10 to 15 microns
70
What microtome is used for cutting celloidin sections
sliding microtome
71
What is the optimum working temperature for cryostat frozen sections
minus 18 to minus 20 degrees Celsius
72
What is the effect if tissue is too cold during frozen sectioning
increased resistance and tissue becomes brittle and fragments
73
What is a common cause of brittle or hard tissue
prolonged fixation+prolonged dehydration+prolonged clearing+prolonged paraffin infiltration+overheated paraffin oven+drying before fixation
74
What is the remedy for brittle or hard tissue
soak in water with detergent phenol or molliflex
75
What causes clearing agent to turn milky when tissue is placed
incomplete dehydration
76
What is the remedy for milky clearing agent
repeat dehydration with absolute alcohol then clear again
77
What causes tissue to smell of clearing agent on trimming
incomplete removal due to insufficient impregnation
78
What is the remedy for clearing agent odor in block
trim block melt wax re-impregnate with paraffin changing paraffin at least once
79
What causes tissue to be opaque and difficult to cut due to presence of alcohol
insufficient clearing
80
What is the remedy for insufficient clearing
repeat clearing or prolong clearing up to twelve hours then re-embed
81
What causes tissue to shrink away from wax when trimmed
insufficient dehydration incomplete clearing and impregnation
82
What is the remedy for tissue shrinking from wax
repeat whole procedure
83
What causes tissue to be soft when block is trimmed
incomplete fixation
84
What is the remedy for soft tissue block
repeat whole procedure
85
What causes compressed wrinkled or jammed sections
blunt or dull knife
86
What is the remedy for compressed wrinkled or jammed sections
re-sharpen the knife
87
What causes air holes in tissue during trimming
incomplete impregnation
88
What is the remedy for air holes in tissue block
repeat impregnation
89
What causes wax to appear crystalline on trimming
contaminated wax or block not cooled rapidly enough
90
What is the remedy for crystalline wax
re-embed in freshly filtered wax
91
What causes paraffin block to be moist and crumble after cooling
insufficient paraffin impregnation
92
What is the remedy for moist crumbling paraffin block
repeat paraffin impregnation then re-embed
93
What causes failure to form ribbons
block surfaces and edges not parallel+horizontal surface not parallel to knife+paraffin too hard+knife tilted too much
94
What is the remedy for failure to form ribbons
re-trim block+re-adjust block+coat edges with lower melting wax+reduce knife tilt
95
What causes sections to be too thick
section thickness set too high+dull knife
96
What is the remedy for thick sections
readjust thickness+hone and strop knife
97
What causes sections to roll up and break against knife edge
blunt knife+too great knife tilt+dirty knife edge
98
What is the remedy for rolling and breaking sections
sharpen knife+reduce tilt+clean knife edge
99
What causes curved crooked or uneven ribbons
blunt or dull spot on knife+edges not parallel+knife not parallel to block+impure paraffin
100
What is the remedy for curved or uneven ribbons
adjust knife+re-trim block+readjust knife and block+repeat impregnation with pure wax
101
What causes squashed sections
lost bevel due to incorrect sharpening
102
What is the remedy for squashed sections
re-sharpen with knife back or automatic sharpener
103
What causes holes in sections
bubble or dirt in embedding medium
104
What is the remedy for holes in sections
re-embed in freshly filtered wax
105
What causes hard spot in tissue due to calcium
incomplete decalcification
106
What is the remedy for hard spot in tissue
use base wedge microtome with wedge knife
107
What causes sections of unequal thickness
too great knife tilt+bevel not cleared+loose clamp set screw+blocks too large or too hard
108
What is the remedy for unequal thickness
reduce tilt+tighten screw+cut smaller fragments+soften blocks in detergent or phenol
109
What causes sections to adhere to knife or microtome parts
static electricity+dirty knife edge+dull knife+too great knife tilt
110
What is the remedy for static electricity
breathe or blow gently on block and knife or increase room humidity
111
What causes ribbon split or vertical scratches
nicks or damage on knife edge+dirty embedding+dirty knife edge+too great knife tilt
112
What is the remedy for ribbon split or scratches
sharpen knife+re-embed in filtered wax+clean knife edge with xylene+reduce tilt
113
What causes sections to lift from knife on upstrokes
too great knife tilt+dull knife+soft paraffin or warm room
114
What is the remedy for lifting sections
reduce tilt+sharpen knife+cool paraffin wax in ice water
115
What causes resistance on lower part of section during cutting
too small knife tilt causing block compression
116
What is the remedy for resistance during cutting
increase knife tilt
117
What causes horizontal or parallel lines or furrows across section
knife edge vibration due to hard tissue
118
What is the remedy for horizontal lines or furrows
treat with phenol during processing or collodionize
119
What causes chatters with thin and thick zones
too great knife tilt
120
What is the remedy for chatters
reduce knife tilt
121
What causes sections to be sometimes thin sometimes thick
blunt knife+improperly clamped knife+too great knife tilt+loose knife or block holder
122
What is the remedy for variable thickness sections
sharpen knife+adjust knife+reduce tilt+tighten screws
123
What causes hard metallic scraping or ringing sound on backstroke
too slanted or too big knife tilt+tissue too hard+knife blade too thin
124
What is the remedy for scraping sound
readjust knife angle+take fresh block treated with phenol+change knife
125
What causes frozen tissue to crumble and come off block holder
inadequate freezing
126
What is the remedy for crumbling frozen tissue
refreeze tissue block
127
What causes frozen tissue to chip into fragments
tissue too hard
128
What is the remedy for chipping frozen tissue
warm tissue with fingers
