02 Sectioning

Question 1

sectioning instrument that allows for the cutting of extremely thin slices of material called section

Answer 1

microtome

Question 2

thickness of sections

Answer 2

4-15 um

Question 3

unit for measurement for the thickness of sections

Answer 3

micron

Question 4

a process where wax is removed with a sharp knife until about 2 mm remains on all sides of the tissues

Answer 4

block trimming

Question 5

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

Answer 5

honing

Question 6

a process of polishing the cutting edge of the knife on leather or canvas done after honing

Answer 6

stropping

Question 7

the angle formed between the cutting edge of the microtome knife

Answer 7

bevel angle (27-32 degrees)

Question 8

the angle formed between the surface of the block and the cutting facet of the knife

Answer 8

clearance angle (5-10 degrees)

Question 9

the straight line formed by intersection of 2 planes, the cutting facets

Answer 9

cutting edge

Question 10

radius of curvature of the cutting edge

Answer 10

0.1 to 0.35 um

Question 11

length of cutting facets

Answer 11

0.1 to 0.6 mm

Question 12

angle between the sides of the knives

Answer 12

wedge angle (15 degrees)

Question 13

angle between upper surface of the cutting facet and the surface of the block

Answer 13

rake angle

Question 14

the ___ (smaller/bigger) the bevel angle, the sharper the knife

Answer 14

smaller

Question 15

ensures that only the cutting edge of the knife touches the specimen block

Answer 15

clearance angle

Question 16

too much clearance causes the knife to ___

Answer 16

chatter

Question 17

knife design and cut type:

extremely sharp, but are also very delicate and are therefore only used with very soft samples

Answer 17

planar concave

Question 18

knife design and cut type:

more stable and find use in moderately hard materials, such as in epoxy or cryogenic sample cutting

Answer 18

wedge profile knives

Question 19

knife design and cut type:

with its blunt edge, raises the stability of the knife, whilst requiring significantly more force to achieve the cut

Answer 19

chisel profile

Question 20

knife design and cut type:

used on sliding, rotary, and rocking microtomes

Answer 20

plano-concave knife

Question 21

knife design and cut type:

used for rocking microtome and sledge microtome

Answer 21

biconcave knife

Question 22

length of biconcave knife

Answer 22

100-250 mm

Question 23

knife design and cut type:

less rigid and prone to vibration; rarely used in histopathology

Answer 23

biconcave knife

Question 24

size of wedge knife

Answer 24

100 - 350 mm

Question 25

knife design and cut type:

most commonly utilized steel knife for routine histopathology; standard knife profile

Answer 25

wedge knife

Question 26

T/F: wedge knife profile cannot be ground as sharp as biconcave and planar-concave knives

Answer 26

T

Question 27

this is caused by defect in the blade edge, calcium, bone or hard material in the specimen

Answer 27

vertical scratches

Question 28

this occurs when the block is faced too aggressively

Answer 28

holes in the section

Question 29

this happens when the specimen is excessively dehydrated or improperly processed

Answer 29

holes in the section

Question 30

tissue adhesive:

background staining may be detected due to its uptake of dyes

Answer 30

albumin

Question 31

added to albumin to increase viscosity and prevent complete drying

Answer 31

glycerol

Question 32

components for Meyer’s egg albumin

Answer 32

equal parts glycerin, distilled water, and egg white

Question 33

added to albumin to inhibit growth of molds

Answer 33

thymol crystal

Question 34

tissue adhesive:

provides firmer attachment than albumin

Answer 34

Gelatin USP

Question 35

tissue adhesive:

greater adhesion than gelatin but stains with many dyes

Answer 35

starch

Question 36

tissue adhesive:

not staining to any appreciable extent with commonly used in stains of histochemical reagents

Answer 36

cellulose

Question 37

tissue adhesive:

used as a general-purpose section adhesive

Answer 37

poly-l-lysine

Question 38

tissue adhesive:

no production of background staining

Answer 38

poly-l-lysine

Question 39

tissue adhesive:

used to improve section adhesion, particularly in immunocytochemistry

Answer 39

poly-l-lysine

Question 40

tissue adhesive:

greatest adhesion; commonly used as an embedding medium for electron microscopy

Answer 40

resins (araldite)

Question 41

tissue adhesive:

a new advancement in section adhesion; can withstand repeated washings with a variety of inorganic solvents

Answer 41

3-Aminopropryltriethoxysilane (APES)

Question 42

tissue adhesive:

used as an adhesive for enhancing chromosome spreading on glass slides and for in situ hybridization of frozen sections

Answer 42

3-Aminopropryltriethoxysilane (APES)

Question 43

type of microtome:

consists of a heavy base and two arms; the lower arm rests on a column and supports the upper, both being pivoted on knife edges which acts as fulcrum

Answer 43

cambridge rocking microtome

Question 44

type of microtome:

the section cutting is affected by the vertical rise and fall of the object against a fixed knife edge

Answer 44

rotary microtome

Question 45

type of microtome:

most widely used, also called Minot microtome

Answer 45

rotary microtome

Question 46

type of microtome:

the knife is stationary and the block is moved up and down in a vertical plane by the rotary action of the hand wheel

Answer 46

rotary microtome

Question 47

type of microtome:

for extremely hard specimens

Answer 47

sliding or base-sledge microtome

Question 48

type of microtome:

has carbon dioxide type or cryostat

Answer 48

freezing microtome

Question 49

type of microtome:

has a knife-horizontal motion

Answer 49

sliding or base-sledge microtome

Question 50

temperature for initial deparaffinization

Answer 50

60-65C