Embedding

Question 1

embedding

Answer 1

enclosing the tissue in infiltration medium (usually paraffin) used for processing and then allowing the medium to solidify

Question 2

embedding medium

Answer 2

typically paraffin, same material as infiltration medium

Question 3

cryoconsole

Answer 3

cold plate on the tissue embedder

Question 4

thermoconsole

Answer 4

hot zone on the tissue embedder

Question 5

molds

Answer 5

used to make the paraffin blocks when embedding, make sure to pick the correct size mold for the tissue you are embedding

Question 6

skin orientation

Answer 6

on edge; epithelium facing one edge of the mold so that all the layers of skin can be seen when cutting through the block

Question 7

tubular structure orientation

Answer 7

ex Fallopian tubes or appendix are embedded in cross-section (of the tube) so that the lumen and all the layers of the mucosa, submucosa, and external muscles can be seen, these sections will appear ring shaped when embedded correctly

Question 8

tissue thickness

Answer 8

tissue cut too thick at the grossing station will be mushy after processing

Question 9

how to fix mushy tissue

Answer 9

pathologist sections the tissue thinner, then tissue goes through 100-95-70% alcohol, followed by refixation in formalin followed by reprocessing

Question 10

tissues with mucosa orientation

Answer 10

in cross-section

Question 11

aggregate specimen orientation (ex endometrial curettings)

Answer 11

in a line down the center of the block

Question 12

what happens when embedding media is overheated

Answer 12

causes tissue to over harden, can also effect tissue morphology

Question 13

embedding tissue on multiple planes

Answer 13

can result in tissue lost when trying to get a section with all pieces in one plane. prevent this by pressing the tissue down uniformly, keeping the paraffin molten enough to get all pieces on the same plane, and work fast while embedding so multiple pieces chill at the same time

Question 14

air bubbles in a tissue block

Answer 14

will cause holes when sectioning, might also lead to cracking of the block while sectioning

Question 15

why is preventative maintenance important?

Answer 15

to ensure that samples are processed and embedded properly, especially when maintenance of temperature comes into play

Question 16

how to embed a tissue specimen

Answer 16

properly process tissue, add liquid paraffin to a mold, allow a film of wax to cool in the bottom of the mold, then add the tissue in the proper orientation, finally place the mold on a cooling plate to finish hardening the rest of the paraffin

Question 17

carbowax

Answer 17

water soluble used for special projects, may be easier to obtain thin sections but tissue remains softer than that in paraffin and sections tend to float out

Question 18

celloidin

Answer 18

nitrocellulose, rarely used except in neuropathology laboratories, staining is tedious and hard to get sections

Question 19

Plastics (glycol methacrylate GMA)

Answer 19

an acrylic resin that is miscible with water, great for hard tissues especially bone or very thin sections, must use glass knives. causes minimal distortion but is difficult to cut, stain, and adhere to slides, also hazardous

Question 20

air bubbles in a tissue block

Answer 20

will cause holes when sectioning

Question 21

30% sucrose

Answer 21

used for frozen sections after being fixed in formalin

Question 22

carbowax

Answer 22

water soluble used for special projects, may be easier to obtain thin sections but tissue remains softer than that in paraffin and sections tend to float out, made of polyethylene glycol and wax

Question 23

epoxy resins

Answer 23

required for electron microscopy, polymerization at 60C resulting in a hard block, require a transitional fluid for clearing