STEP 1: FIXATION (unfinished)

Question 1

used as a mordant to perform special staining

Answer 1

secondary fixative

Question 2

post-chromatization is a form of secondary fixation where a primarily fixed tissue is placed in aqueous solution of __________________ for 24 hours as a mordant

Answer 2

2.5-3% potassium dichromate

Question 3

used to wash out chromates, formalin, and osmic acid

Answer 3

tap water

Question 4

used to wash out excess amount of picric acid

Answer 4

50-70% alcohol

Question 5

used to wash out excess mercuric fixation

Answer 5

alcoholic iodine

Question 6

fixative becomes part of the tissue

Answer 6

additive fixation

Question 7

fixative stability by forming cross-links

Answer 7

additive fixation

Question 8

fixative is not incorporated into the tissue

Answer 8

non additive fixation

Question 9

stability by removing bound water attached to H-bonds of certain groups within the protein molecule

Answer 9

non additive fixation

Question 10

fixation temperature for surgical specimens

Answer 10

room temp

Question 11

fixation temperature for electron microscopy and … histochemistry

Answer 11

0-4C

Question 12

fixation temperature for bacteriology and blood films

Answer 12

heat

Question 13

fixation temperature for urgent biopsies

Answer 13

formalin heated to 60C

Question 14

fixation temperature for tissues with tuberculosis

Answer 14

formalin at 100C

Question 15

thickness of section for electron microscopy

Answer 15

1-2 mm^2

Question 16

thickness of section for for light microscopy

Answer 16

2 cm^2 or no more than 0.4 cm

Question 17

osmolality that gives best results

Answer 17

slightly hypertonic solutions

Question 18

isotonic solutions cause…

Answer 18

cell swelling

Question 19

volume of fixative

Answer 19

should be 10-20 times the volume of tissue

Question 20

fixation is retarded by…

Answer 20

size and thickness
presence of mucus
presence of fat
presence of blood
cold temperature

Question 21

fixation is enhanced by…

Answer 21

size and thickness
agitation

Question 22

choice of fixative and mode of processing is dependent on…

Answer 22

need for immediate examination
tissue structure or component to be studied
type of tissue
staining technique to be applied
type of section to be made

Question 23

characteristics of a good fixative

Answer 23

cheap
stable
safe to handle
kills cells quickly
inhibits bacterial decomposition and autolysis
permits rapid and even penetration of tissues
harden tissues
isotonic
makes cellular component insoluble to hypotonic solitions
permits subsequent application of many staining procedures

Question 24

a primary component common in nuclear fixatives

Answer 24

glacial acetic acid

Question 25

pH of nuclear fixative

Answer 25

4.6 or less

Question 26

pH of cytoplasmic fixatives

Answer 26

> 4

Question 27

fixative that must never contain glacial acetic acid

Answer 27

cytoplasmic fixatives

Question 28

aldehyde fixative

Answer 28

formaldehyde
10% formol-saline
10% neutral buffered formalin of phosphate buffered formalin
formal-corrosive
alcoholic formalin
glutaraldehyde

Question 29

commercially available solution of formaldehyde

Answer 29

10% formalin

Question 30

fixation time for formalin

Answer 30

24 hours

Question 31

formalin concentration unsatisfactory for routine fixation

Answer 31

40% formalin

Question 32

a “tolerant” fixative

Answer 32

formalin

Question 33

disadvantage: reduces basophilic and eosinophilic staining of cells

Answer 33

unbuffered formalin

Question 34

disadvantage: forms abundant brown pigment granules on blood-containing tissues

Answer 34

unbuffered formalin

Question 35

recommended for central nervous tissues and general post-mortem tissues

Answer 35

10% formol-saline

Question 36

ideal for most staining techniques

Answer 36

10% formol-saline

Question 37

disadvantage: metachromatic reaction of amyloid is reduced

Answer 37

10% formol-saline

Question 38

10% formol-saline is a simple microanatomical fixative made up of…

Answer 38

saturated formaldehyde diluted to 10% with sodium chloride

Question 39

recommended for preservation and storage of surgical, post mortem and research specimens

Answer 39

10% Neutral Buffered Formalin or Phosphate-Buffered Formalin (pH 7)

Question 40

best fixative for tissues containing iron pigments and elastic fibers

Answer 40

10% Neutral Buffered Formalin or Phosphate-Buffered Formalin (pH 7)

Question 41

for routine post-mortem tissues

Answer 41

formal-Corrosive (Formal-Sublimate)

Question 42

advantage: no need for “washing out”

Answer 42

formal-Corrosive (Formal-Sublimate)

Question 43

disadvantage: forms mercuric chloride deposits

Answer 43

formal-Corrosive (Formal-Sublimate)

Question 44

disadvantage: does not allow frozen sections to be made

Answer 44

formal-Corrosive (Formal-Sublimate)

Question 45

disadvantage: inhibits the determination of the extent of tissue decalcification

Answer 45

formal-Corrosive (Formal-Sublimate)

Question 46

aka Gendre’s fixative

Answer 46

alcoholic formalin

Question 47

used to fix sputum

Answer 47

alcoholic formalin fixative

Question 48

good for preservation of glycogen and for micro-incineration technique

Answer 48

alcoholic formalin fixative

Question 49

made up of two formaldehyde residues linked by three carbon chains

Answer 49

glutaraldehyde

Question 50

used for small tissue fragments and needle biopsies

Answer 50

2.5% glutaraldehyde

Question 51

recommended for larger tissues less than 4mm thick

Answer 51

4% glutaraldehyde

Question 52

recommended for enzyme histochemistry and electron microscopy

Answer 52

glutaraldehyde