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200 clinical foundations > w11 > Flashcards

w11 Flashcards

1
Q

histology

A

study of microscopic structure of tissue

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2
Q

what is used as a fixative after biopsy or autopsy

A

10%v/v neutral buffered formalin to prevent degradation of tissue

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3
Q

when is tissue given accession number

A

once it arrives in history accessioning department

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4
Q

Histology accessioning

A

check patient info then accession it into LIS-generate barcoded labels for container, slides, and documents and a printer will put accession number onto cassette
s in accession number for surgical and a for autopsy, 2 digit for year then a case number.

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5
Q

4 steps in preparing tissue for microscope

A
  1. gross dissection
  2. tissue processing
  3. embedding
  4. sectioning
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6
Q

what is done during gross dissection?

A

pathologist or pathology assistant does it
-whole specimen examined and described for size, colour, texture and anomalies.
then representative sections are dissected and blasted into tissue cassette- remainder stored for 2-4 weeks

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7
Q

what goes on in tissue processing

A

cassettes loaded onto automated tissue processor which flood tissues in a series of solutions to fix, dehydrate, clear, and fill with wax

  1. fixation-formalin
  2. dehydration-alcohol
  3. clearing-xylene
  4. infiltration-paraffin
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8
Q

what occurs during the fixation process of tissue processing

A

preserves micro anatomy of tissue by preventing autolysis and bacterial decomp.- allows tissue to withstand treatment
done with 10% formalin (formaldehyde)

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9
Q

dehydration of tissue processing

A

removal of water, done with graded alcohol 70% then 80% then 95% then 100%

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10
Q

what is done during clearing process of tissue processing

A

-replaces alcohol with xylene- this is necessary because alcohol and paraffin are not miscible

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11
Q

infiltration of tissue processing

A

done with molten paraffin wax 60 degrees celsius

-replaces clearing agent, and completely permeates tissue and hardens

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12
Q

how VIP tissue processor works

A

-draw fluid by vacuum to tissue compartment then it is pumped back into storage container takes 1-2 hours or up to 16 hours

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13
Q

chemicals used in tissue processor

A

dangerous -hazardous fumes that are flammable, consult SDS and wear PPE - work in well ventilated room free of ignition -r95 can be worn.

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14
Q

what happens if volume of chemicals in tissue processor not sufficient

A

-poor or incomplete processes (dehydrating,clearing, infiltrating)

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15
Q

what to do if water removal incomplete (inadequate dehydration)? - tissue block soft and mushy tissue block

A

(carry over of water from incomplete dehydration the xylene will become murky and white)
to fix: reverse the processing steps to remove wax from tissue then repeat dehydration
melt was from tissue, then use xylene, then use alcohol, t

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16
Q

what is miscible in xylene

A

alcohol and paraffin

-it can remove both

17
Q

what happens if alcohol is not completely removed and what to do

A
  • it will prevent paraffin from penetrating tissues adequately and it will be soft and mushy and difficult to section
  • reverse process to remove wax from tissue block and repeat, dehydration, clearing and infiltration with fresh reagents
18
Q

tissue processor maintanence

A

temp checks on processing fluids- 40-45 degrees celsius. molten paraffin stored at 60
-purge cycle is after infiltrating tissue it removes paraffin for next batch (pumps xylene in and out of chamber multiple times)

19
Q

embedding

A

done by MLT wax-infiltrated tissue placed in small metal mold- more paraffin used the end product is a block of tissue which is sectioned into 3-5 micrometers

20
Q

sectioning

A

microtome slices tissue block 3-5 micrometers thick, they are floated out on warm water to remove wrinkles. then picked up on glass slide, placed in oven at 60 degrees to melt paraffin and fix slide

21
Q

staining

A

reverse of tissue processing since distilled water is used so they are hydrated or brought to water
1.removal of paraffin wax with xylene
2. removal of xylene with alcohol most to least 100-70
3.water to remove alcohol
H&E hematoxylin and eosin used
hematoxylin- nuclei blue eosin- cytoplasm red

22
Q

special stains

A

-demonstrate specific types of tissue, structures or chemical components within tissue

23
Q

tips for good stain results

A
  • check reagent expiry
  • never allow slides to dry out
  • keep reagents covered
  • filter stains
  • follow schedule for changing reagent
  • monitor water quality
  • microscopically check staining
  • stain solutions accurately prepared
24
Q

dehydration, clearing and mounting (occurs after staining)

A
  • dehydration with graded alcohols to gradually remove water
  • clearing agent is miscible with alcohol and with resinous mounting media like xylene
  • mounting- applying cover slip this will protect stained tissue for storage and microscopic analysis
25
Q

who exams slides

A

anatomic pathologist - microanatomis and gross examination used to diagnose disease states

26
Q

how long are tissues and slides stored for

A

30-50 years 50 years for childrens hospital

27
Q

what are frozen specimens used for?

A

used on surgical specimens while patient still in operating room and a rapid diagnosis required

28
Q

decalcification

A

-if it is bone or calcium salts are present: calcium must be removed by nori acid or EDTA(chelates calcium)

29
Q

cytology

A

study of structure of cells-detect malignant cells. -two categories gynaecological and non gynaecological

30
Q

gynecological specimens

A

bulk of cytology
cervical and vaginal brushings collected during pelvis exam
tissue prep automated and run by MLA -stained with Papanicalaou stain-routine stain

31
Q

papanicolaou stain

A

routine stain
three stains: -hematoxylin, - organs g, -eosin-based -several rinsing procedures and differentiating, hydration and dehydration can take 20-25 mins

32
Q

non-gynaecological specimens

A

sputum, gastric specimens, CSF, urine, pleural fluid, peritoneal fluids.

33
Q

full through process of tissue in histology (16)

A
  • accessioning
  • gross dissection (then representative selections)
  • tissue processing
  • -fixation (formalin)
  • -dehydration (increasing alcohol)
  • -clearing xylene
  • -infiltration with paraffin wax
  • embedding-put in tissue block and section onto slides
  • staining (hydrate or bring back to water)
  • remove paraffin with xylene
  • remove xylene with alcohol
  • remove alcohol with water
  • stain with hematoxylin and eosin
  • dehydrate with alcohol
  • clean with xylene
  • mount
34
Q

storage time of gynaecological original specimen, non-gynaecological original specimens, normal cyto slides, abnormal cyto slides

A

gynaecological original specimen- 4 weeks
non-gynaecological original specimens- 1 week
normal cyto slides- 5 years
abnormal cyto slides-30 years

35
Q

MLA duties in histo and cyto

A
  • receive and accessioning
  • resolve errors
  • prepare specimens for microscopic examination
  • prepare reagents
  • load instruments
  • maintain instruments
  • qc
  • filing and retrieval of specimens
  • reagent waste
  • specimen waste

200 clinical foundations (16 decks)

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