Histo Lec Module 2 Unit 5

Question 1

process where alcohol or dehydrating agent is removed and replaced by a substance that will dissolve the wax

Answer 1

clearing or dealcoholization

Question 2

process where alcohol or dehydrating agent is removed and replaced by a substance that will dissolve the wax

Answer 2

clearing or dealcoholization

Question 3

clearing agent imparts optical property due to its

Answer 3

high refractive index

Question 4

volume of clearing agent

Answer 4

40 times the tissue volume

Question 5

clearing time for a small biopsy

Answer 5

1 hr

Question 6

clearing time for larger tissues

Answer 6

3 changes with 60 minutes each

Question 7

end point of clearing

Answer 7

transparent tissue

Question 8

prolonged exposure to clearing ageng makes tissue

Answer 8

brittle, more difficult to cut

Question 9

wax that is more readily replaced by paraffin has ___ boiling point

Answer 9

lower

Question 10

clearing agent that causes tissue shrinkage and hardening but is affordable and acts rapidly

Answer 10

xylene

Question 11

better at preserving tissue structure and does not garden tissue, but is slower acting and can cause tissue shrinkage

Answer 11

toluene

Question 12

xylene can clear within

Answer 12

15 -30 mins

Question 13

acts rapidly, does not harden or shrink tissue but is carcinogenic and highly flammable

Answer 13

benzene

Question 14

used for tough tissues like skin, fibroid and decalcified tissues because they can process thick tissues and large spcimens. it is however slower and not transparent

Answer 14

chloroform

Question 15

used for processing CNS tissues and cytological studies of smooth muscle and skin because it causes mininal shrinkage, can be used at indefinite time without causing damage. it does not produce uniform quality however, and is hard to eliminate from tissues

Answer 15

cedarwood oil

Question 16

not recommended for routin clearing but used for embryos, insects and delicate specimens. it can clear 70% alcohok without shrinkage and hardening

Answer 16

aniline oil

Question 17

most used xylene replacement

Answer 17

lemonene

Question 18

used for celloidin sections, and has slow, gentle, and non hardening action

Answer 18

terpenes

Question 19

has lowest hazard rating among all clearing agents and can be used in place of xylene. but it can breakdown compounds if not pure or stable

Answer 19

orange-oil based

Question 20

toxic clearing agent that is now restricted by the governement

Answer 20

chlorinated hydrocarbon

Question 21

it is efficient, nonhazardous, less expensive, causes less shrinkage, does not lose quality or detail, but solidifies at lower temperature

Answer 21

coconut oil

Question 22

it produces good tissue, is nontoxic, non flammable, biodegradable, economic, easy to handle and readily available

Answer 22

bleached palm oil

Question 23

causes minimum shrinkage but it dissolves celloidin, produces brittle tissue which tend to be adulterated

Answer 23

clove oil

Question 24

similar to chloroform, dangerous to inhale on prolonged exposure but cheapaer

Answer 24

carbon tetrachloride

Question 25

superior to ordinary clearing agents because it perofroms 2 processes at a time which shortens total processing time, and is non toxic

Answer 25

tetrahydrofuran

Question 26

used when time is important because tossues may be embedded 4 hours after fixation due to its miscibility in both water and paraffin. it causes greater shrinkage hiwever and have toxic fumes

Answer 26

dioxane

Question 27

process by which clearing agent is removed and replaced by a medium that completely fills tissue cavities and give firm consistency to tissues

Answer 27

infiltration or impregnation

Question 28

clearing agent that takes longer time to infiltrate

Answer 28

cedarwood oil

Question 29

accelerates the infiltration process

Answer 29

vacuum

Question 30

simplest, most common embedding medium

Answer 30

paraffin wax

Question 31

most common melting point of paraffin wax for histological use

Answer 31

56 - 58 degrees Celsius

Question 32

recommended use of paraffin wax

Answer 32

2 celsius above melting point

Question 33

pressure applied within a vacuum embedding iven

Answer 33

760 mmHg

Question 34

vacuum embedding redices embedding time by

Answer 34

25-75%

Question 35

mixture of highly purified paraffin and synthetic plastic polymers

Answer 35

paraplast

Question 36

melting point of paraplast

Answer 36

56-57 C

Question 37

permits large dense tissue blocks such as bines and brain to be cut easily

Answer 37

paraplast

Question 38

less brittle and less compressible paraffin substitute

Answer 38

embeddol

Question 39

lower melting point but harder than paraffin

Answer 39

ester wax

Question 40

melting point of ester wax

Answer 40

46-48 degrees

Question 41

soluble in 95% alcohol meaning that it can be used without clearing

Answer 41

ester wax

Question 42

most used water soluble wax

Answer 42

carbowax

Question 43

suitable for enxyme histochemical studies

Answer 43

carbowax

Question 44

proprietart blends of plastic plymer paraffin waxes

Answer 44

dimethyl sulphoxide

Question 45

scavenges residual transition solvent and alters tissue permeability by substituting or removing bound water

Answer 45

dimethyl sulphoxide

Question 46

suitable for specimens with large hollow cavities, hard dense tissues, laegre tissues and soft tissues with mixed consistency

Answer 46

celloidin

Question 47

celloidin is supplied as

Answer 47

thin (2%) medium (4%) thick (8%) solutions dissolved in equal parts ether and alcohol

Question 48

three types of celloidin infiltration

Answer 48

wet mount, dry mount, low viscosity nitrocellulose

Question 49

difference between wet and dry mount celloidin

Answer 49

wet - 70% alcohol for bines teeth and large brain sections | dry- Gilsons mixture of chloroform and cedarwood oil for whole eyes

Question 50

some advantages of cellodin impregnation

Answer 50

rubbery consistency, does not require heat, less shrinkage and distortion

Question 51

some disadvantages of celloidin

Answer 51

slow infilitration difficult to cut thin sections cannot make serial sections difficult to get photomicrographs

Question 52

rarely infiltration medium used except when dehydration is avoided

Answer 52

gelatin

Question 53

used for frozen sections

Answer 53

gelatin

Question 54

thickness of tissues in gelatin infiltration

Answer 54

2-3 mm

Question 55

prevents growth of mold in gelatin

Answer 55

1% phenol

Question 56

other terms for embedding

Answer 56

casting blocking

Question 57

impregnated tissue is positioned in a nold that is allowed to solidify

Answer 57

embedding

Question 58

if the embedding medium is too soft

Answer 58

torn or shredded sections

Question 59

embedding medium too hard

Answer 59

brittle tissues that will shatter

Question 60

arrangement of tissue in a precise position during embedding, microtomy, and before staining

Answer 60

orientation

Question 61

4 types of mold

Answer 61

Leukharts embedding mold Compound embedding unit Plastic embedding ring disposable embedding molds

Question 62

two L shaped strios of heavy brass or metal

Answer 62

Leukharts embedding mold

Question 63

can be adjusted to the size of the specimen

Answer 63

leukhart

Question 64

series of interlocking plates resting on flat metal base

Answer 64

compound embedding unit

Question 65

special stainless steel base mold and fitted with block holder

Answer 65

plastic embedding rings and base mold

Question 66

equipped with warm plate, cold plate, and white plastic cassette molds with snap on lid

Answer 66

tissue tek

Question 67

three types of disposable embedding molds

Answer 67

peel away plastic ice trays paper biats

Question 68

tissues are first infiltrated with supporting medium such as agar or nitrocellulose then infiltrated a second time with paraffin

Answer 68

double embedding

Question 69

obsolete due to difficulty of tissue samples to adhere to slides and limiting of tissue expansion

Answer 69

agar as preembedding medium

Question 70

three types of plastic embedding medium

Answer 70

epoxy polyester acrylic

Question 71

hydrophobic, may reduce antigenicity, and carcinogenic

Answer 71

epoxy

Question 72

large molecules so slowly infiltrates

Answer 72

bisphenol A Araldite

Question 73

mixture of isomers that has lower viscosity

Answer 73

glycerol (epon)

Question 74

purena di filtrae the fastest

Answer 74

cyclohexene dioxide (spurr)

Question 75

made for EM but now seldom used

Answer 75

polyester

Question 76

extremely hydrophilic, tough when dehydrated, and used for TEM and preferable to use when high resolution light microscopy is needed

Answer 76

glycol methacrylate (GMA)

Question 77

where the tissue is held into position

Answer 77

block holdet

Question 78

for actual cutting of the sections

Answer 78

knife carrier and knife

Question 79

to line up tissue block in proper position with the knifex adjusting proper thickness for successive sections

Answer 79

pawl, ratchet feed wheel and adjustment screws

Question 80

hard sharpening

Answer 80

honing

Question 81

removal of nicks on the knife edge to remove blemishes

Answer 81

coarse honing

Question 82

grinding the cutting edge of the knife on a stone tk acquire even edge

Answer 82

honing proper

Question 83

for manual sharpening when cutting edge has been rendered blunt or nicked and usually gives best results

Answer 83

belgium yellow

Question 84

gives more polishing effect then belgium yellow

Answer 84

arkansas

Question 85

much coarser than the first 2 types and used only for badly nicked knives followed by either of the two

Answer 85

fine carborundum

Question 86

direction of honing

Answer 86

heel to toe

Question 87

to poliish and sharpen the cutting edge

Answer 87

stroping

Question 88

used in stroping

Answer 88

horse leather