Dehydration

Question 1

Process of removing intercellular and extracellular water from the tissue following fixation and prior to impregnation.

Answer 1

Dehydration

Question 2

Removal of water by evaporation from a solid, semi-solid, or liquid.

Answer 2

Drying

Question 3

Slow substitution of the water in the tissue with an organic solvent

Answer 3

Dehydration

Question 4

True or False.

The amount of dehydrating agent in each step should not be greater than 10 times the volume of the tissue.

Answer 4

False.

(The amount of dehydrating agent in each step should not be less than 10 times the volume of the tissue)

Question 5

What is the preferred concentration of alcohol?

Answer 5

70-90%

Question 6

What is the most common dehydrating agent?

Answer 6

Ethanol

Question 7

What is the alcohol concentration for delicate tissues like embryonic tissues?

Answer 7

30%

Question 8

What is the usual duration when using ethanol for dehydration?

Answer 8

1-2 hours

Question 9

How many changes will you do to ensure the complete removal of water when dehydrating with alcohol?

Answer 9

2

Question 10

What is placed 1/4 inch deep in the bottom of the container to ensure complete dehydration?

Answer 10

anhydrous copper sulfate

Question 11

What indicates the full saturation of dehydrating fluids with water?

Answer 11

blue discoloration of copper sulfate crystals

Question 12

What type of alcohol-dehydrating agent is considered the best dehydrating agent whereby it mixes with water and many organic solvents?

Answer 12

Ethyl alcohol (ethanol)

Question 13

True or False.

Never leave tissues in 95% or 100% ethanol for more than 2 hours.

Answer 13

True

Question 14

What alcohol-dehydrating agent is considered the best dehydrating agent for blood smears?

Answer 14

Methyl alcohol

methanol

Question 15

What alcohol-dehydrating agent is used for plant and animal micro-technique?

Answer 15

Butyl alcohol

Question 16

What alcohol-dehydrating agent is used undiluted with water?

Answer 16

High Grade Alcohol

Question 17

What dehydrating agent is used for tissue perfusions however causes brittleness?

fixative and dehydrating agent

Answer 17

Acetone

Question 18

For how long does acetone dehydrates a tissue?

Answer 18

1/2 - 2 hours

Question 19

What dehydrating agent removes most lipids?

Answer 19

Acetone

Question 20

What dehydrating agent is referred to as an excellent dehydrating and clearing agent?

Answer 20

Diethylene dioxide

dioxane

Question 21

What is the refractive index of diethylene dioxide?

dioxane

Answer 21

1.42

Question 22

What is the boiling point of diethylene dioxide?

Answer 22

101.5℃

Question 23

What refers to the method whereby the tissue is wrapped in a gauze bag and suspended in a bottle containing dioxane and a little anhydrous calcium oxide?

Answer 23

Weiseberger’s Method

Question 24

What is the duration period of the dehydration when using Weiseberger’s method?

Answer 24

3-24hrs

Question 25

# dehydrating agent: * rapid, but toxic when inhaled, ingested, and when in contact with skin * combustible at 110-120°C * **non-harmful to tissues**

Answer 25

Ethylene glycol monoethyl ether | cellusolve

Question 26

What is the boiling point for cellusolve?

Answer 26

156.4℃

Question 27

What is the combustion point for ethylene glycol ethers?

Answer 27

110-120℃

Question 28

What dehydrating agent is not used anymore?

Answer 28

triethyl phosphate

Question 29

What is the boiling point for triethyl phosphate?

Answer 29

215℃

Question 30

What dehydrating agent is toxic if inhaled and ingested?

Answer 30

tetrahydrofuran (THF) + cellusolve

Question 31

What dehydrating agent is the most toxic dehydrating agent?

Answer 31

carbon tetrachloride

Question 31

What is the additive for 95% ethanol that softens tissues?

Answer 31

4% phenol

Question 32

In transmission electron microscopy, what dehydrating solvent solubilized lipid?

Answer 32

ethanol

Question 33

In transmission electron microscopy, what refers to the **transition fluid** that is very reactive even at low temperatures?

Answer 33

propylene oxide

Question 34

What is a good substitute for propylene oxide?

Answer 34

acetonitrile