fixation

Question 1

fixatives that chemically alter the tissue by bonding and linking with it

Answer 1

additive fixatives

Question 2

fixatives - predominantly organic compounds - that act on tissues without chemically combining with it

Answer 2

non-additive fixatives

Question 3

fixatives that allow solutions to penetrate the interior of the tissues readily

Answer 3

coagulant fixatives

Question 4

fixatives that act by creating gel barriers that make it more difficult for solutions to penetrate tissues

Answer 4

non-coagulant fixatives

Question 5

placing an already fixed tissue in a second fixative to act as mordant

Answer 5

secondary fixation

Question 6

form of secondary fixation in which a tissue is placed in 2.5-3% potassium dichromate for 24 hours for better staining effects

Answer 6

post-chromatization

Question 7

process of removing excess fixative after fixation to improve staining and remove artifacts

Answer 7

washing out

Question 8

effect of temperature on fixation

Answer 8

increase in temperature accelerates fixation (but increases rate of autolysis)

Question 9

fixation time for brain specimens

Answer 9

2-3 weeks

Question 10

ideal ratio of fixative to specimen volume

Answer 10

20:1 (or 10:1)

Question 11

interval between interruption of blood supply and the time the tissue is immersed in a fixative

Answer 11

cold ischemia time

Question 12

maximum allowable cold ischemia time

Answer 12

60 minutes

Question 13

duration of fixation for electron microscopy

Answer 13

3 hours

Question 14

pH required for satisfactory fixation

Answer 14

pH 6-8

Question 15

types of fixatives according to composition

Answer 15

simple and compound fixatives

Question 16

types of fixatives according to action

Answer 16

microanatomical and cytological fixatives

Question 17

type of fixatives made up of only one component substance

Answer 17

simple fixatives

Question 18

type of fixatives made up of two or more components to obtain optimal combined effect

Answer 18

compound fixatives

Question 19

type of fixatives that permit the general microscopic study of tissues without altering its structural patterns

Answer 19

microanatomical fixatives

Question 20

type of fixatives that preserve specific parts and particular microscopic elements of the cell itself

Answer 20

cytological fixatives

Question 21

cytological fixative that contains glacial acetic acid and has a pH of 4.6 or less

Answer 21

nuclear fixatives

Question 22

cytological fixative that should never contain glacial acetic acid and has a pH of more than 4.6

Answer 22

cytoplasmic fixatives

Question 23

cytological fixative that preserve the chemical constituents of cells and tissues

Answer 23

histochemical fixatives

Question 24

fixative that is both a nuclear and histochemical fixative

Answer 24

newcomer’s fluid

Question 25

these fixatives are satisfactory for routine paraffin sections, electron mx and when histochemical and enzyme studies are indicated

Answer 25

aldehyde fixatives

Question 26

fixative used for mailing specimen

Answer 26

formaldehyde (formalin)

Question 27

used to remove brown or black ppts by the action of formic acid in formaldehyde with blood

Answer 27

saturated picric acid

Question 28

best fixative for tissues containing iron pigments and elastic fibers

Answer 28

10% BNF

Question 29

rapid fixative that is used to fix sputum because it coagulates mucus

Answer 29

Gendre's fixative (alcoholic formalin)

Question 30

fixative used to fix brain tissue for the diagnosis of rabies

Answer 30

Carnoy's fluid

Question 31

fixative recommended for chromosomes, lymph glands and urgent biopsies

Answer 31

Carnoy's fluid

Question 32

most rapid fixative; fixation time: 1-3 hours

Answer 32

Carnoy's fluid

Question 33

fixative recommended for mucopolysaccharides and nuclear proteins

Answer 33

Newcomer's fluid

Question 34

excellent microanatomical fixative for blood-containing organs

Answer 34

zenker's-formol (Helly's fluid)

Question 35

fixative recommended mainly for tumor biopsies

Answer 35

Heidenhain's Susa

Question 36

fixative for the study of tissue necrosis and early degenerative processes

Answer 36

Orth's fluid

Question 37

fixative that demonstrates rickettsiae and other bacteria

Answer 37

Orth's fluid

Question 38

fixative recommended for fixation of embryos and pituitary biopsies

Answer 38

Bouin's solution

Question 39

expensive and slow-penetrating fixative for special application in neurohistology and neuropathy

Answer 39

osmium trioxide

Question 40

fixative recommended for the study of water diffusible enzymes esp. phosphates and lipases

Answer 40

acetone