TEST II

Question 1

what name is given to a tissue taken from a patient for histological examination

Answer 1

Biopsy

Question 2

What process involves a water bath

Answer 2

Tissue flattening

Question 3

A specimen is examined for identification of specimen/specimen site, name of patient or any unique patient identifier, this statement is true for

Answer 3

Tissue accessioning

Question 4

in histology what holds the specimen from tissue processing up to sectioning

Answer 4

Tissue cassette

Question 5

Mention any three devices/apparatus needed during microscopic tissue examination in histology department

Answer 5

1. Ruler
2. Digital scale
3. Tissue cassette

Question 6

what is the proper tissue fixation ratio for adequate tissue fixation

Answer 6

10:1 or 20:1

Question 7

which of the following statements is true about tissue fixation

Answer 7

Fixatives can also preserve tissue chemicals

Question 8

Removal of alcohol from tissue

Answer 8

Clearing

Question 9

During tissue processing, infiltration is done

Answer 9

after clearing

Question 10

The first step in hematoxylin and eosin staining procedure is

Answer 10

Removal of parafin wax from the tissue

Question 11

Which of the following can be used as a blueing agent in hematoxylin and eosin staining procedure

Answer 11

any of the above

Question 12

mention one advantage of manual tissue processing compared with automated tissue processing

Answer 12

Ability for closer monitoring and intervention during the process, With manual processing, the technician can visually inspect the tissue at each stage. This allows them to identify any potential problems, such as uneven fixation or excessive dehydration, and take corrective measures if necessary.

Question 13

How do the agitation(stirring) influence the rate of tissue processing

Answer 13

Agitation increases the rate of reaction as molecules of agents and tissue coride

Question 14

How do the temperatures influence the rate of tissue processing

Answer 14

Higher temperatures generally accelerate the rate of chemical reactions involved in tissue processing. This translates to quicker dehydration, clearing, and paraffin infiltration, leading to shorter processing times.

Question 15

In tissue processing, the stage after fixation is dehydration.
Why is this stage important

Answer 15

Dehydration removes water from the tissue, making it compatible with the embedding medium, allowing for proper infiltration of the wax throughout the sample

Question 16

mention any one example of a dehydration agent

Answer 16

acetone alcohol

Question 17

Mention any three criteria for choosing a clearing agent

Answer 17

1.The clearing agent should be chosen with safety in mind
2. must be cheap
3.The clearing agent should effectively clear the tissue while preserving its morphological integrity

Question 18

One precaution during tissue flattening using water bath is that the temperature should not reach melting point of paraffin wax or any embedding medium used. Explain the reason for this precaution.

Answer 18

Distortion and Loss of Tissue: If the water bath gets too hot and exceeds the melting point of the paraffin wax, the wax that has already infiltrated the tissue will start to melt. This melted wax can disrupt the delicate cellular structures within the tissue, leading to distortions and artifacts in the final slide.

Question 19

mention any two examples of embedding media apart from paraffin wax

Answer 19

1. Epoxy Resins
2. Cryo-embedding Media
3. Gelatin

Question 20

Apart from the tissue block itself, mentioned any three items needed during microtomy

Answer 20

microtome
soft brush
water bath

Question 21

which of the following are facts concerning tissue clearing agents

Answer 21

all of the above

Question 22

explain any two ways how dehydrating agents work

Answer 22

1. Gradient Replacement: Dehydrating agents, typically alcohols like ethanol, work by gradually replacing the water content within the tissue through a process called gradient replacement.
2. Lowering Water Activity: Dehydrating agents also function by lowering the water activity (Aw) of the tissue environment

Question 23

not one fixative is ideal. agree or diagree

Answer 23

each specimen has its advantages and disadvantages and each one works best on a different specimen than the other

Question 24

mention an example of dehydrating, coagulative fixative

Answer 24

acetone

Question 26

for good fixation results tissue thickness should not be more than?

Answer 26

5 mm

Question 27

Mention any two fixatives that should be avoided including situations when that do not allow their use

Answer 27

1. Formaldehyde: avoid when working in poorly ventilated areas. Also avoid using formaldehyde if you need to preserve immunological epitopes in your samples, as it can affect their reactivity.
2. Picric Acid. avoided when working around heat or open flames due to its high explosion risk

Question 28

mention ant two things that are done during microscopic tissue examination before tissue processing

Answer 28

1. Gross Examination
2. Selection and Trimming

Question 29

In terms of use what is the difference between an adhesive and embedding medium

Answer 29

Adhesives and embedding mediums both serve to hold things together, but in different ways. Adhesives create a bond between two surfaces, like glue. Embedding mediums, on the other hand, surround and support an object entirely, often used in science for things like tissues or fossils. In short, adhesives connect surfaces while embedding mediums encapsulate objects.

Question 30

Two reasons why too high concentration of fixative should be avoided

Answer 30

1. A very strong fixative concentration can over-harden the sample, making it difficult to stain or perform further analysis
2. High fixative concentrations can cause the sample to shrink or distort its natural shape.

Question 31

How does cold temperature affect rate of tissue fixation

Answer 31

Colder temperatures slow down the chemical reactions involved in fixation. This means it takes longer for the fixative to penetrate the tissue and cross-link the molecules, leading to a slower overall fixation process.

Question 32

Must harden the tissue making cutting of sections easier but prevent over hardening what is the proceeding statement all about

Answer 32

embedding process with paraffin wax

Question 33

what is the use of embedding media celloidin

Answer 33

Celloidin excels at supporting tissues that are naturally hard or prone to crumbling during sectioning