Staining Techniques

Question 1

What does Hematoxylin stain?

Answer 1

Hematoxylin is positively charged/basophilic and will stain negative parts of the cells blue (nucleus, nucleous, RER)

Question 2

What does Eosin stain?

Answer 2

Eosin is negatively charged/acidophilic and will stain positive parts of the cell pink/red (cytoplasmic filaments, intracellular membranous components, most proteins)

Question 3

What is an acidophilic stain?

Answer 3

Reacts with cationic (+) groups

Question 4

What is a basophilic stain?

Answer 4

Reacts with anionic (-) groups

Question 5

What does Trichrome stain?

Answer 5

Used to distinguish between collagen and muscle

Question 6

Mallory vs. Masson Trichrome staining

Answer 6

Mallory stains collagen sky blue vs Masson stains collagen greenish-blue

Question 7

Elastic stain plus H&E

Answer 7

Used to stain elastic fibers which stain black/purple. Ex Aldehyde fuchsin is an elastic stain

Question 8

What does silver stain identify?

Answer 8

Reticular fibers are stained black with silver stain in lymph nodes and spleen

Question 9

What does Periodic Acid-Schiff (PAS) stain?

Answer 9

Carbohydrates, which are usually washed out by preparation, are stained with carbohydrates (mucus) and basement membrane a red-ish color

Question 10

What does Alcian blue stain?

Answer 10

Acidic mucus - carbohydrate

Question 11

What does oil red O stain?

Answer 11

Lipids - fixation with formalin removed lipids, but staining with oil red O will stain lipid droplets as red droplets, as opposed to H&E in which you assume the presence of the lipid in empty blank spheres

Question 12

What does osmium tetroxide stain?

Answer 12

Lipids - staining them dark brown/black, such as myelin sheaths, stains by crosslinking lipids

Question 13

Phase-contrast microscopy

Answer 13

Used for visualizing unstained, unpigmented living cells

Question 14

Darkfield microscopy

Answer 14

Used to increase the contrast of small objects in unstained specimens

Question 15

Polarizing microscopy

Answer 15

Filter blocks unrotated light from reaching the eyepiece, such that only well-ordered structures are visible - such as cystalline or paracrystalline array - MTs, collagen fibers

Question 16

Fluorescence microscope

Answer 16

Detects molecules with fluorescence that emit visible light when exposed to specific UV wavelengths

Question 17

Confocal scanning microscope

Answer 17

produces an optical section of unsectioned specimen, can see different layers of whole object

Question 18

Enzyme Histochemistry

Answer 18

Product of the enzyme reaction is precipitated, and the product is visualized rather than the enzyme

Question 19

Immunohistochemistry

Answer 19

Used to detect specific proteins of interest, requires antibodies

Question 20

Autoradiography

Answer 20

Used to localize newly synthesized macromolecules in cell and tissue sections through incorporation of tagged molecule, usually Tritium H3