Dehydration

Question 1

The step that removes intracellular and extracellular water after fixation

Answer 1

Dehydration

Question 2

The primary purpose of dehydration in histology

Answer 2

Prepares tissues for embedding by making them wax-miscible

Question 3

Standard processing temperature for dehydration

Answer 3

Room temperature

Question 4

Technical term for water-removing solvents

Answer 4

Dehydrants

Question 5

Chemical classification of dehydrating agents

Answer 5

Organic solvents

Question 6

The standard alcohol concentration progression

Answer 6

70% to 100% alcohol

Question 7

Special concentration for fragile tissue types

Answer 7

30% ethanol

Question 8

Minimum recommended dehydrant-to-tissue ratio

Answer 8

10:1

Question 9

Which alcohol is recommended for routine tissue dehydration?

Answer 9

Ethanol (Ethyl Alcohol)

Question 10

Which dehydrating agent is considered the best for most tissue processing?

Answer 10

Ethanol

Question 11

What are four key physical properties of ethanol?

Answer 11

Clear, colorless, flammable, fast-acting

Question 12

Why is ethanol good at mixing with both water and other solvents?

Answer 12

It mixes with water and many solvents

Question 13

What advantage does ethanol have regarding tissue penetration?

Answer 13

Penetrates tissues easily

Question 14

What safety advantage does ethanol have over other alcohols?

Answer 14

Non-poisonous (with precautions)

Question 15

What practical advantage does ethanol have regarding cost?

Answer 15

Inexpensive

Question 16

Which alcohol is primarily used for blood and tissue films?

Answer 16

Methanol (Methyl Alcohol)

Question 17

What special preparation type commonly uses methanol?

Answer 17

Smear preparations

Question 18

What is the most significant safety concern with methanol?

Answer 18

Very toxic - can cause blindness

Question 19

Which alcohol is commonly used in plant and animal microtechniques?

Answer 19

Butanol (Butyl Alcohol)

Question 20

What is the main characteristic of butanol’s dehydration speed?

Answer 20

Slow-acting

Question 21

What advantage does butanol have regarding tissue effects?

Answer 21

Causes less shrinkage

Question 22

Rank these alcohols by dehydration speed: Ethanol, Methanol, Butanol

Answer 22

Fastest: Methanol → Ethanol → Butanol (slowest)

Question 23

Which alcohol would you choose for minimal tissue shrinkage?

Answer 23

Butanol

Question 24

Which alcohol should be avoided due to blindness risk?

Answer 24

Methanol

Question 25

Which alcohol is safest for routine use: Ethanol, Methanol, or Butanol?

Answer 25

Ethanol

Question 26

Which clear, colorless, highly miscible and flammable dehydrant works in 30 mins to 2 hours?

Answer 26

Acetone

Question 27

What are three major disadvantages of using acetone for dehydration?

Answer 27

Causes shrinkage/brittleness, removes lipids, not generally recommended

Question 28

What dual-function agent serves as both dehydrant and clearing agent?

Answer 28

Dioxane

Question 29

What three substances is dioxane miscible with?

Answer 29

Paraffin, alcohol, and xylene

Question 30

What tissue advantage does dioxane provide during dehydration?

Answer 30

Produces less tissue shrinkage

Question 31

What special capability does dioxane have regarding tissue storage?

Answer 31

Allows long-term tissue storage

Question 32

What are three disadvantages of dioxane?

Answer 32

Expensive, poor ribboning, extremely toxic

Question 33

Which dioxane method uses pure dioxane with paraffin?

Answer 33

Graupner's method

Question 34

Which method suspends tissue in gauze with dioxane and anhydrous copper calcium oxide?

Answer 34

Weisberger method

Question 35

What rapid dehydrant allows long-term storage without distortion?

Answer 35

Cellosolve (Ethylene Glycol Monoethyl Ether)

Question 36

At what temperature range does cellosolve become combustible?

Answer 36

110-120°F

Question 37

Which body systems are particularly vulnerable to cellosolve toxicity?

Answer 37

Reproductive, urinary, and cardiovascular systems

Question 38

Which dehydrant removes water readily with minimal distortion?

Answer 38

Triethyl Phosphate

Question 39

What is triethyl phosphate particularly good at preventing in tissues?

Answer 39

Hardening

Question 40

When is triethyl phosphate most commonly used?

Answer 40

For dehydrating sections and smears after staining

Question 41

What dual-purpose agent both dehydrates and clears tissues?

Answer 41

Tetrahydrofuran

Question 42

This dissolevs fat, other substances, and improves staining results.

Answer 42

Tetrahydrofuran

Question 43

What are three major hazards of tetrahydrofuran?

Answer 43

Toxic if ingested/inhaled, strong offensive odor, causes conjunctival irritation

Question 44

What essential safety precaution is required when using tetrahydrofuran?

Answer 44

Must be used in well-ventilated area

Question 45

What are the factors involved when considering the strength of initial alcohol concentration?

Answer 45

Tissue size and nature; Type of fixatuve used.

Question 46

What alcohol concentration can you store tissue for only a set period of time (not any longer)?

Answer 46

70-80%

Question 47

Why can't you place tissue in less than 70% aclohol?

Answer 47

It will get macerated.

Question 48

Why can't you store tissue at 70-80% aclohol for very long periods?

Answer 48

It will interfere with staining.

Question 49

At what temperature is dehydration hastened?

Answer 49

37 Celsius

Question 50

This serves as an indicator that accelerates complete dehydration via removing water from the used agent.

Answer 50

Annhydrous Copper Sulfate