Infiltration and embedding

Question 1

Process whereby the clearing agent is completely removed from the tissue & replaced by a medium that
will completely fill all the tissue cavities, thereby giving a firm consistency to the specimen

Answer 1

impregnation

Question 2

the process by which the impregnated
tissue is placed into a precisely arranged position in a mold containing a
medium which is then allowed to solidify

Answer 2

embedding

Question 3

the simplest, most common and best embedding
medium used for routine tissue processing.

Answer 3

paraffin

Question 4

Paraffin is solid at room temperature but melts at temperatures up to about

Answer 4

65-70C

Question 5

not recommended for fatty
tissues.

Answer 5

paraffin wax

Question 6

Three ways by which Paraffin wax impregnation and
embedding may be performed

Answer 6

• manual processing
• automatic processing
• vacuum embedding

Question 7

The machine is mounted on
rollers to permit the turning of
platforms and easy access to
beakers and wax baths

Answer 7

Elliott bench type processor

Question 8

The clearing agent and the dilute ethanols should be changed

Answer 8

at least once a week.

Question 9

Wax bath thermostats should be set at least

Answer 9

3 degrees above the melting
point of the wax

Question 10

involves wax impregnation under negative
atmospheric pressure inside an embedding oven.

Answer 10

Vacuum embedding

Question 11

recommended for urgent biopsies

Answer 11

vacuum embedding

Question 12

Substitutes for Paraffin Wax

Answer 12

Paraplast
Ester wax
Water soluble waxes

Question 13

Not soluble in water but soluble in 95%EA, can be
used for impregnation without prior clearing of
tissue

Answer 13

Ester wax

Question 14

does not require dehydration and clearing

Answer 14

carbowax

Question 15

• suitable for many enzyme histochemical studies

Answer 15

carbowax

Question 16

suitable for specimens with large hollow cavities which tend to collapse

Answer 16

celloidin

Question 17

It does not require heat during processing

Answer 17

celloidin

Question 18

recommended for bones, teeth, large brain sections and whole organs

Answer 18

Wet Celloidin Method

Question 19

preferred for processing of whole eye sections

Answer 19

Dry Celloidin Method

Question 20

Gilson’s mixture

Answer 20

equal part of chloroform and cedarwood oil

Question 21

example of plasticizer

Answer 21

oleum ricini or castor oil

Question 22

rarely used except when dehydration is to be avoided and when tissues are to be subjected to histochemical and
enzyme studies

Answer 22

Gelatin impregnation

Question 23

After impregnation, the tissue is placed into a mold
containing the embedding medium and this medium is
allowed to solidify.

Answer 23

embedding

Question 24

the process by which a tissue is arranged in precise positions in the mold during embedding, on the
microtome before cutting, and on the slide before
staining

Answer 24

orientation

Question 25

used to be recommended for embedding hard tissues such as bones and teeth, and for large sections of whole organs

Answer 25

Celloidin or Nitrocellulose Embedding Method

Question 26

used to control the rate of the evaporation of the solvent

Answer 26

bell jars

Question 27

recommended for making small sections of celloidin blocks.

Answer 27

double embedding