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UND 362 embedding
| Question | Answer |
|---|---|
| what is the purpose of embedding (blocking/casting) | encase tissue uniformly, create uniform density, demonstrate a desired structure |
| what types of media are used in embedding | paraffin, celloidin/nitro cellulose, agar/gelatins, resins |
| give a positive and negative to paraffin per tissue | inexpensive/universally used, NEG. heat used in processing step (infiltration) damages IHC |
| what is celloiding/nitro cellulose used for? | brain microtomy (requires no heat, but takes a LONG time) |
| what is a drawback to using agar/gelatin | takes a LONG time to process |
| give 4 factors and a disadv for using resins | used for EM, some use heat or UV to polymerize, need glass or diamond knife, need special microtome attachment if used for light microscope. disadv - many resins are toxic/carcinogenic |
| what occurs if paraffin is rapidly cooled when embedding | smaller crystal size therefore it will adhere closer to margin of tissue |
| give factors about metal molds | various sizes, need to be cleaned, can be reused |
| give factors about plastic molds | no cleanup, have static electricity, not reusable, biopsies can get stuck to edges |
| give the gen. rules and QC to embedding | block label on top, tissue face down, light pressure applied to embed flat. QC # of specs in cassette, specific orientation, verification to accompanying logs |
| give steps for embedding | *one cassette at a time*. Select mold size, fill mold w/paraffin, orient spec. embed on same plane, cover with cass. and fill w/ wax, cool immediately |
| describe large flat tissue orientation | use pressure so all is at same level, flat edge down |
| describe elongated tissue orientation | diagonal, narrow surface to microtome knife first |
| describe multiple desity tissue (bone and soft tissue) orientation | soft tissue must be present to knife first |
| describe tubular tissue orientation | (fall, vas def, app, temp. artery) - done in cross section (tire on its side) |
| describe epithelial (w/ wall) tissue orientation (ie GI, skin, cystic structure) | All are done on edge (cystic structure ala dome would have cut/flat side down) |
| describe multiple spec tissue orientation | done in a line (if skin it would have that cut last by knife) |
| describe bone tissue orientation | put in diagonally ( with hard surface cut last) |
| what is forcep metastasis | fragments accidentally moved from one block to another |
| describe needle bx's tissue orientation | either verticle or diagonal (not desirable is random nor parallel horizontally) |
| if tissue is inked or has a notch on the top how should it be orientated | ink side or notch up (per the book) |
Created by:
mustangvxd
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