Unit 4 Part 2 - Histology Flashcards
the study of tissue
histology
main function of histology dept
prepare slides of tissue from various sources for the pathologist to examine
to preserve tissue and prevent structural change, preserves it as close as possible to living state
fixation
critical step in preparation of histological sections, tissues are preserved from decay to prevent autolysis or putrefaction
fixation
fixative should be ___ more than the volume of the specimen
15-20 times
most common fixative
10% NB (neutral buffered) formalin
difference between formaldehyde and formalin?
formaldehyde - gas
formalin - liquid
mixing 40% formaldehyde with 100 ml of water gives us
formalin
to get 10% formalin
10 ml of 100% formalin + 90 ml of water
it is the addition of ___ that causes the substance to be called formalin instead of formaldehyde
methyl alcohol
to get neutral buffered formalin, add buffers
- sodium dihydrogen phosphate monohydrate
- disodium hydrogen phosphate anhydrous
formalin will fix 4mm piece of tissue in ___
8 hours
Factors that affect fixation
- temperature
- time
- penetration
- specimen dimensions
minimum time tissue are placed in 10% NB formalin
24 hours
how long is a brain fixed for
2 weeks
initial step in the examination of clinical specimen
gross description
two end products of gross examination
- document of findings
- set of tissue blocks, portions sealed in cassettes for processing and microscopic examination
3 types of tissue in histo
routine specimens (appendix)
small tissue biopsy (colon bx)
urgent specimens (breast bx)
what does this label mean:
2014 S 7654 A2
2014 - year
S - surgical
7654 - specimen #
A - 1st container
2 - 2nd block
VIP machine
vacuum infiltration processor
an automated tissue processor that does the dehydration, clearing, and wax infiltration
VIP machine
sections of tissue embedded in wax block are cut in a series of ribbons, with a thickness of 3-5 um
microtomy
most common stain in histology
hematoxylin and eosin stain (H&E)
a microtome operated in low temp cabinet (-30°C)
cryostat
stain for carbohydrates
periodic acid shiff (PAS)
stain for elastic in arteries or cartilage
orcein
stain for lipids
oil red o
stain for H. pylori, stomach ulcers
toluidine blue
stain for reticulum, melanin, fungus
silver stain
how to file blocks and slides
reverse chronological order (most recent closest to you)
blocks are kept ____, either on site or off site
permanently
slides are kept ___
for min 5 years
the study of cells in terms of structure, function and chemistry
cytology
main purpose of cytology
is to look for cancerous changes to cells
3 main categories of cytology
- gynaecological
- non-gynaecological
- fine needle aspirations
stains used in cytology
- papanicolaou stain
- romanowsky-type stain
used for gynecologic and fixed non-gynecologic samples
papanicolaou stain
example of non-gynecological fixed specimen
urine specimen
fixative for urine specimen for cytology
50-70% alcohol
most common test done in cytology is the
pap smear
stain used for pap smear is Papanicolaou stain for __ details
nuclear
if air-dried gynecologic preparations ____ technique is preferred
Romanowsky-type staining
Papanicolaou stain involves ___ dyes in ___ solutions
5 dyes
3 solutions
what does hematoxylin stain and what color does it stain?
nuclei, blue
most common hematoxylin stain
harris’ hematoxylin
what is the first acidic counterstain in papanicolaou stain and what does it stain?
orange green 6 (cytoplasmic stain)
what is the second counterstain in papanicolaou stain?
Eosin Azure
what does Eosin Y do in Papanicolaou stain?
gives pink color to cytoplasm
what does light green SF stain do in Papanicolaou stain?
stains cytoplasm blue
the staining technique used in hematology and cytopathology, used to differentiate cells for microscopic examination in pathological specimens
romanowsky staining
romanowsky-giemsa
study of diseased cells
cytopathology
used to transfer any sedimentable particles from liquid suspension onto a microscope slide, but is primarily used to transfer biological cells
cytocentrifugation (cytospin)
specimen prep mainly used for cervical smears
ThinPrep
specimen prep similar to histology
cell block prep
in cell block preparation, once supernatant is removed, 2-3 drops of ___ are placed in centrifuge tube
histogel