H&E

Question 1

highlight and differentiate tissue components and allow them to be seen under the microscope

Answer 1

biological dyes

Question 2

most common staining technique used in histology

Answer 2

hematoxylin and eosin

Question 3

dyes have a greater affinity for _______ molecules than solvent molecules

Answer 3

tissue

Question 4

the result of attractive forces between the dye molecule and molecules within the tissue

Answer 4

affinity

Question 5

affinity of dyes for tissue elements is affected by 4 factors

Answer 5

-structure of dye molecule
-shape of dye molecule
-charge distribution of dye
-solvent characteristics

Question 6

determines attractive or repulsive characteristics of the dye

Answer 6

charge distribution

Question 7

attracted to negatively charged molecules

Answer 7

hematoxylin

Question 8

attracted to positively charged molecules

Answer 8

eosin

Question 9

pH largely determines this

Answer 9

charge

Question 10

pH of hematoxylin should be

Answer 10

2.2-2.8

Question 11

oxidation of hematoxylin forming the active dye ingredient

Answer 11

hematein

Question 12

hematoxylin is a natural dye extracted from the wood of this tree

Answer 12

Logwood

Question 13

this can oxidize hematoxylin to hematein

Answer 13

sodium iodate

Question 14

oxidation can also occur with this exposure

Answer 14

air

Question 15

hematein produces a precipitate that must be _________ before use

Answer 15

filtered

Question 16

this is required to help link hematoxylin to a desired tissue

Answer 16

mordants

Question 17

metal salts often used in histology as a mordant

Answer 17

aluminum and iron

Question 18

need hematoxylin and hematein mixture as this occurs

Answer 18

oxidation

Question 19

need ______ to dissolve the dry powder dye which acts as a carrier of the dye

Answer 19

solvent such as water

Question 20

example of progressive staining

Answer 20

frozen section

Question 21

tissue is left in the staining solution just long enough to reach desired endpoint

Answer 21

progressive staining

Question 22

deliberately overstaining where the dye completely saturates all tissue elements

Answer 22

regressive staining

Question 23

a popular regressive stain

Answer 23

Harris Hematoxylin

Question 24

this is preferred when a very clear differentiation of tissue elements is desired

Answer 24

regressive staining

Question 25

tissue is selectively destained using this process

Answer 25

differentiation

Question 26

you need to do this in progressive staining

Answer 26

monitoring, to see if it is staining correctly

Question 27

this is achieved by using a dilute acid/acid alcohol

Answer 27

differentiation

Question 28

removes excess background staining

Answer 28

differentiation

Question 29

the ions in the differentiation solution diffuse more rapidly than the dye molecule which causes what

Answer 29

release of the loosely attached dye

Question 30

differentiation is halted by this when the end point is reached

Answer 30

water rinse

Question 31

the process of shifting the color from purplish to blue by the application of a weak alkaline solution

Answer 31

bluing

Question 32

bluing agents are typically _______ with a pH of 7.5-9.0

Answer 32

alkaline

Question 33

enhance the contrast of H&E by increasing the crispness of hematoxylin

Answer 33

bluing agents

Question 34

used in both progressive and regressive staning

Answer 34

bluing

Question 35

counter stain used to demonstrate the general architecture of the tissue and provide contrast to the now stained nuclei

Answer 35

eosin

Question 36

acidic dye that binds to the basic parts of the cell (cytoplasm)

Answer 36

eosin

Question 37

erythrocytes and keratin will be this color with eosin

Answer 37

red or orange

Question 38

collagen will be this color with eosin

Answer 38

pink

Question 39

smooth muscle will be this color with eosin

Answer 39

dull pink

Question 40

pH of eosin

Answer 40

4.0-4.5

Question 41

eosin should have how many shades under a scope

Answer 41

3

Question 42

what should hematoxylin depict under a scope

Answer 42

nuclear membrane and stained chromatin

Question 43

rushing through this step can result in spotty staining

Answer 43

deparaffinization

Question 44

too light hematoxylin occurs due to (4)

Answer 44

-too many slides -short staining time -overdecalcified removing nucleic acids -autolysis or poor fixation

Question 45

too dark hematoxylin occurs due to (4)

Answer 45

-long staining time -short destaining time -laser surgery -metallic sheen from overoxidation

Question 46

too light eosin can occur if (2)

Answer 46

-alcohol rinse after stain was too long or too aqueous -short staining time

Question 47

one tone of eosin indicates (2)

Answer 47

poor fixation or overstaining