Dehydration

Question 1

to remove fixative and water from the tissue and replacing them with dehydrating fluid in preparation for impregnation.

Answer 1

Dehydration

Question 2

True or false:

Dehydrating fluids are generally used in increasing strengths.

Answer 2

True

Question 3

This means that all the aqueous tissue fluids are removed but with little disruption to the tissue due to diffusion currents

Answer 3

Increasing strengths

Question 4

What are the increasing grades of alcohol?

Answer 4

65-75% EtOH -> 95% EtOH -> 100% Absolute Alc

Question 5

For delicate tissues, particularly embryonic and animal tissues, it is recommended to start processing with ____?

Answer 5

30% ethyl alcohol

Question 6

Ratio of Dehydrating Agent to tissue?
Ratio of Fixative to tissue?

Answer 6

DA - T : 10:1
F - T : 20:1

Question 7

True or false: (Characteristics of an ideal dehydrating solution)

1. It should dehydrate rapidly without producing considerable shrinkage or distortion of tissues
2. It should evaporate very fast
3. It should not dehydrate fatty tissues
4. It should not harden tissues excessively
5. It should remove stains
6. It should not be toxic to the body
7. It should not be a fire hazard

Answer 7

True:
1, 4, 6, 7,

False:
2, 3, 5,

Question 8

What is the most commonly used dehydrating agent?

Answer 8

Alcohol

Question 9

▪ an alcohol type for routine dehydration of tissues.
▪ BEST DEHYDRATING AGENT

Answer 9

Ethanol

Question 10

▪ an alcohol type employed for blood and tissue films
▪ can cause blindness (optic blindness)
▪ also osmium tetroxide

Answer 10

Methyl alcohol

Question 11

▪ an alcohol type utilized in plant & animal micro techniques
▪ slow (maBagal = Butyl)

Answer 11

Butyl alcohol

Question 12

▪ ethanol + small amount of methanol;
▪ used in the same way as ethanol

Answer 12

Industrial methylated spirit
(denatured alcohol)

Question 13

▪ many of the processing methods for use in a
microwave oven recommend this alcohol type

Answer 13

Isopropyl alcohol

Question 14

What type of alcohol can cause blindness, like osmium tetroxide?

Answer 14

Methyl alcohol

Question 15

What is known as a slow type of alcohol?

Answer 15

Butyl alcohol

Question 16

What is known as BOTH fixative and dehydrating agent?

Answer 16

ACETONE

Question 17

What are the different types of alcohol as agent?

Answer 17

EMBII (EMPI ALCOHOL)

Ethanol
Methyl alcohol
Butyl alcohol
Industrial methylated spirit (denatured alcohol)
Isopropyl alcohol

Question 18

What is the organ for acetone?

Answer 18

Brain or CNS

Question 19

What bodies does acetone preserves?

Answer 19

Negri bodies

Question 20

This D.A is known for rapid but penetrates poorly

Answer 20

Acetone

Question 21

True or false:

ACETONE is not recommended for routine use

Answer 21

True

Question 22

Dioxane is also known as?

Answer 22

Diethylene dioxide

Question 23

What are the D.As that are BOTH for dehydrating and clearing?

Answer 23

Dioxane (Diethylene oxide)
Cellosolve (Ethylene glycol monoethyl ether)
Tetrahydrofuran (THF)

Question 24

What D.A has an advantage as excellent dehydrating and clearing agent?

Answer 24

Dioxane

Question 25

In this D.A, Tissues can be left for long periods of time without affecting the staining properties of the specimen ?

Answer 25

Dioxane

Question 26

This D.A has a disadvantage of **expensive and produces toxic vapos**

Answer 26

Dioxane

Question 27

What are the 2 method in DIoxane?

Answer 27

Graupner's and Weiseberg method

Question 28

This method includes 3x changes of dioxane and paraffin both for dehydration and clearing

Answer 28

Graupner's method

Question 29

This method involves wrapping the tissue with gauze (add dioxane + anhydrous calcium oxide)

Answer 29

Weiseberg Method

Question 30

Cellosolve is also known as?

Answer 30

Ethylene glycol monoethyl ether

Question 31

What is the disadvantage of cellosolve?

Answer 31

It is combustible at 110-120F

Question 32

What is the D.A known for fast dehydrating?

Answer 32

Cellosolve

Question 33

Cellosolve should be put on what kind of temperature and container, due to its disadvantage?

Answer 33

in cold temp, and explosion proof container

Question 34

If methyl alcohol can cause **blindess**, what dehydrating agen can cause **conjunctival irritation**?

Answer 34

Tetrahydrofuran (THF)

Question 35

In THF, other than it is toxic and cause eye, skin irritants, what are the other disadvantages?

Answer 35

Offensive odor and it dissolves fat (it shouldn't)

Question 36

Used to dehydrate smears producing **minimal shrinkage**

Answer 36

Triethyl phosphate

Question 37

What additives acts as a tissue softener for hard tissues such as tendons, nails, or dense fibrous tissues?

Answer 37

4% phenol (tissue softener) + each 95% ethanol baths

Question 38

What can act as BOTH dehydrating agent and an indicator of water content of the last bath (100% ETOH)?

Answer 38

Andhydrous copper sulfate

Question 39

In anhydrous copper sulfate, what color indicates presence of water?

Answer 39

BLUE

Question 40

what serves as an indicator that dehydration is complete? and at what color?

Answer 40

Anhydrous copper sulfate - white blue

Question 41

What turns **milky** when it has water?

Answer 41

Xylene

Question 42

how many stations does dehydration have?

Answer 42

5 stations