netpath notes

Question 1

what does hematoxylin do?

Answer 1

basic dye that stains acids blue = basophilic
nucleic acids of nuclei will therefore be blue
rER can aso stain blue because of the high RNA content

Question 2

what does eosin do?

Answer 2

acid dye that stains basic structures red to pink = acidophilic/eosinophilic
most cytoplasmic elements are pink

Question 3

what does it mean for a substance to be amphophilic?

Answer 3

stains with both H and E dyes => blue-pink color

Question 4

what is the trichrome stain for?

Answer 4

used to identify connective tissue
collagen = blue to green
nuclei = black
cytoplasm = brick-red

Question 5

what is the reticulin stain for?

Answer 5

for reticulin (type of fiber in connective tissue - made of type III collagen - secreted by reticular cells)
stains black

Question 6

what is the PAS stain for?

Answer 6

for structures with a high proportion of carbohydrate macromolecules (such as glycogen, glycoprotein, proteoglycans)
such as connective tissues, mucus, and basal laminae
will not stain for collagen
will stain for fungi
stains basal membrane dark

Question 7

what does mucicarmine stain for? what is mucin?

Answer 7

colors epithelial mucins rose to red
mucins = chemically heterogeneous group of glycoprotein substances secreted by a variety of cells, including many glandular epithelial cells (aka mucus)
mucicarmine therefore stains for secretory epithelial cells

Question 8

what is prussian blue used to stain for?

Answer 8

for iron - makes iron a dark blue

Question 9

how would you detect iron in tissue?

Answer 9

in H&E, it’ll look rusty colored

prussian blue will stain it blue

Question 10

what is the grocott methenamine silver (GMS) stain for?

Answer 10

stains cell walls of fungi black
blue counterstain used to visualize underlying tissue
used to visualize organisms in tissue

Question 11

what is the acid fast stain used for?

Answer 11

to visualize organisms in the tissue

magenta-color stain is held in organisms after treatment with alcohol - used for mycobacteria such as tubercle bacilli

Question 12

how are brown stains made (procedure)?

Answer 12

type of immunostaining
first antibody is to whatever’s being stained for (eg rabbit anti-IgG) and second is for the first antibody (eg mouse anti-rabbit) and has peroxidase, which will turn the regions where the antibody attached brown

Question 13

what will a liver stained with reticulin look like?

Answer 13

liver cords are bordered by reticulin

portal triad area is rich in reticulin

Question 14

which stains can be used to stain for microorganisms?

Answer 14

AFB - can see mycobacteria
GMS - for fungi
PAS - most fungi

Question 15

what causes caseous necrosis?

Answer 15

certain types of infections, specifically those caused by mycobacteria and fungi

Question 16

how will caseous necrosis appear different from liquefacative or coagulative necrosis?

Answer 16

won’t be complete cell dissolution as in liquefactive

but also won’t have crisp preservation of cell outlines as in coagulative necrosis

Question 17

where would you expect to see fat necrosis?

Answer 17

areas that have experienced trauma
but most often result of action of lipases (then it’s enzymatic fat necrosis)
most commonly seen in acute pancreatitis because acinar cells get injured and activate and release pancreatic enzymes that destroy the pancreatic tissue and fat cells around the gland
breat, pancreas, subcutaneous tissue

Question 18

how would fat necrosis appear histologically?

Answer 18

white in gross sections
amorphous in microscopic
can still see outlines of the dead adipocytes

Question 19

what makes up the amorphous material seen in fat necrosis?

Answer 19

the cells die and release TG
the TG is converted to free FA
FA complex with Ca => soaps

Question 20

how would fatty liver appear histologically?

Answer 20

in gross images, yellow-grey color (should be brown-red)
would feel slimy or greasy
fat would be in hepatocytes

Question 21

what is stromal fatty infiltration?

Answer 21

when fat cells grow between parenchymal cells
occurs in obese individuals particularly and also in the elderly if their organs undergo atrophy - normal cells replaced by fat

Question 22

what types of changes in hyalin might you see histologically? when would you see these changes?

Answer 22

homogenous glass pink arterial wall in patients with diabetes mellitus
using trichrone stain, can detect that this wall has more collagen than would be normal

in amyloidosis (deposition of amyloid in cells) - in glomerulus

mallory bodies (see other card)

Question 23

what are mallory bodies? what do they look like histologically? what patients would you expect to see them in?

Answer 23

aggregates of intermediate filaments
in hepatocytes of patients with alcoholic hepatitis mostly
glassy, eosinophilic appearance

Question 24

what does hyaline mean?

Answer 24

refers to a homogenous, glassy pink appearance in routine H&E sections

Question 25

what is hemosiderin? what does it mark for?

Answer 25

form in which iron is stored in cells

marker of previous hemorrhage

Question 26

what are anthracotic particles? where would they be found?

Answer 26

carbon dust in inspired air that is phagocytosed by pulmonary macrophages
appear in cytoplasms of macrophages as fine black particles
in lung - smear of sputum

Question 27

what is hemosiderin? where would you expect to see it? what would it look like histologically?

Answer 27

golden brown pigment - breakdown product of hemoglobin
gets phagocytized by macrophages

found in areas where there was a hemorrhage

will stain blue with prussian blue stain
will be brown/rust-colored in H&E

Question 28

what is lipofuscin (aka lipochrome)? what would it look like histologically? what cells would you expect to see it in?

Answer 28

wear-and-tear pigment - waste/indigestible residues of autophagic vacuoes formed during aging and atrophy

finely granular yellow-brown pigment in cytoplasms

see in cells that have really long life spans such as myocardial fibers and neurons

Question 29

what is brown atrophy?

Answer 29

when lipofuscin gives an organ a brownish hue

this isn’t dangerous to the organ

Question 30

how would Ca salts appear histologically?

Answer 30

usually basophilic and so are blue in H&E

Question 31

what is the usual consequence of ischemia?

Answer 31

coagulative necrosis

Question 32

what is the usual consequence of infection?

Answer 32

liquefactive necrosis if inflammatory response involves may neutrophils

if inflammatory response is granulomatous, may be caseous necrosis

Question 33

what is hypertrophy? is it reversible?

Answer 33

enlargement of cells without an increase in cell number (so organ gets bigger because cells get bigger, rather than there being more cells)
very often reversible

Question 34

how would hypertrophy appear histologically?

Answer 34

cells are larger

nuceli become square

Question 35

what is hyperplasia? is it reversible?

Answer 35

increase in the number of cells of an organ but cells are normal size (so organ gets bigger but cells don’t)
may be reversible depending on what’s driving it - if hormonal stimulus and hormone is removed many of the new cells will become apoptotic and die

Question 36

what cells can cause hyperplasia?

Answer 36

two cell types can be stimulated to divide by trophic factors:

1: labile cells - constantly dividing (eg bone marrow stem cells, intestinal crypt epithelial cells)
2: stable - enter cycle only if there’s a need (eg liver cells, renal tubular cells)

Question 37

what would hyperplasic tissue look like?

Answer 37

in breast, lobules hypertrophy, so much more cellular - acini become bigger, more complex, and there’s more of them

in prostate - lots of infoldings in glands

Question 38

what is metaplasia? what are some examples?

Answer 38

reversible phenomenon when one adult cell type is replaced by another - phenotype changes
replacement tissue can survive under circumstances when normal, more fragile tissue couldn’t
usually under pathological stimulus
can develop to dysplasia

eg - normally have pseudostratified columnar epi in airways - cigarette smoking will cause them to become nonkeratinized squamous epithelium
or if acid indigestion - get change to mucous secreting epithelium in esophagus to protect it - replaces squamous epithelium = Barrett’s esophagus

Question 39

what is dysplasia?

Answer 39

deranged development
lack of appropriate maturation
but not neoplastic yet
at gross level = abnormal development - overall disorganization of cells of various types and not failure of normal differentiation of a single cell type
but more common at the histologic level - at cellular level implies alteration of size, shape and organization of cells
often failure of normal diff of one type of cell

Question 40

what would dysplasia look like histologically?

Answer 40

severe will have atypical cellular changes eg nuclear enlargement and inappropriate increase in number or location of mitotic cells

disordered maturation, enlarged nuclei, failure of a normal degree of progressive differentiation (ie from more internal to external layers)

Question 41

what is hypoplasia?

Answer 41

failure to grow to normal size (as opposed to atrophy, which is shrinking to a smaller than normal size)

Question 42

what happens if growth stimulant is applied to “permanent” cells?

Answer 42

nuclei may enlarge

Question 43

what is atrophy? what would it look like histologically?

Answer 43

cells shrink, but there’s no decrease in the number of cells
organ therefore decreases in size
often see just nuclei (no cytoplasm)