Fixation is the _______ of tissues by stabilizing proteins to resist further changes.
Fixation is the killing, penetration, and hardening of tissues by stabilizing proteins to resist further changes.
The primary goal of fixation is to _______ as close to their living state as possible.
The primary goal of fixation is to preserve cells and tissues as close to their living state as possible.
The secondary goals of fixation are to _______ and _______.
The secondary goals of fixation are to harden tissue for cutting and protect against handling trauma.
The ideal time to perform fixation after tissue removal is _______ following interruption of blood supply.
The ideal time to perform fixation after tissue removal is 20–30 minutes following interruption of blood supply.
The recommended volume ratio of fixative to tissue for maximum effectiveness is _______.
The recommended volume ratio of fixative to tissue for maximum effectiveness is 20 parts fixative to 1 part tissue.
Formalin diffuses into tissue at a rate of approximately _______.
Formalin diffuses into tissue at a rate of approximately 1 mm per hour.
A fixative should have a pH range between _______.
A fixative should have a pH range between 6.0 and 8.0.
The preferred osmolality for fixatives is _______; hypertonic causes cell shrinkage, hypotonic causes swelling.
The preferred osmolality for fixatives is slightly hypertonic or isotonic; hypertonic causes cell shrinkage, hypotonic causes swelling.
Two additive fixatives are _______ and _______.
Two additive fixatives are formaldehyde and glutaraldehyde.
Two non-additive fixatives are _______ and _______.
Two non-additive fixatives are acetone and ethanol.
The recommended fixative for electron microscopy is _______ because it preserves lipids and provides excellent ultrastructural detail.
The recommended fixative for electron microscopy is osmium tetroxide because it preserves lipids and provides excellent ultrastructural detail.
The fixative traditionally used for general histopathology that is tolerant for mailing specimens is _______.
The fixative traditionally used for general histopathology that is tolerant for mailing specimens is 10% neutral buffered formalin.
The fixative recommended for enzyme histochemistry is _______ or _______.
The fixative recommended for enzyme histochemistry is 4% formaldehyde or formol saline.
10% formalin is composed of _______ diluted to 1 L with distilled water.
10% formalin is composed of 100 mL of 37–40% formaldehyde diluted to 1 L with distilled water.
Formol corrosive is formed by combining _______ with _______.
Formol corrosive is formed by combining formaldehyde with mercuric chloride.
The three main methods of paraffin wax infiltration are _______, _______, and _______.
The three main methods of paraffin wax infiltration are manual, automatic, and vacuum.
The melting point of routine paraffin wax is _______ and it cannot be used for _______.
The melting point of routine paraffin wax is 56 °C and it cannot be used for fatty tissues.
Two substitutes for paraffin wax are _______ (melting point 56–57 °C) and _______ (melting point 46–48 °C).
Two substitutes for paraffin wax are Paraplast (melting point 56–57 °C) and Ester wax (melting point 46–48 °C).
The concentration and time for thin celloidin infiltration is _______.
The concentration and time for thin celloidin infiltration is 2–4% for 5–7 days.
The section thicknesses for paraffin, celloidin, frozen, and ultrathin are: Paraffin: _______, Celloidin: _______, Frozen: _______, Ultrathin (EM): _______.
The section thicknesses for paraffin, celloidin, frozen, and ultrathin are: Paraffin: 4–6 µm, Celloidin: 10–15 µm, Frozen: 4 µm, Ultrathin (EM): 0.5 µm.
The most commonly used microtome for routine paraffin sections is the _______.
The most commonly used microtome for routine paraffin sections is the rotary microtome.
The bevel, clearance, and wedge angles for a microtome knife are: Bevel: _______, Clearance: _______, Wedge: _______.
The bevel, clearance, and wedge angles for a microtome knife are: Bevel: 27–32°, Clearance: 0–15°, Wedge: 14–15°.
Honing grinds off nicks with oil stones using _______, while stropping polishes on leather using _______.
Honing grinds off nicks with oil stones using 20–30 strokes, while stropping polishes on leather using 40–120 strokes.
Three methods of deparaffinization are _______, _______, and _______.
Three methods of deparaffinization are flame, xylene immersion, and 55–60 °C oven incubation.
Three adhesives used for slide attachment are _______, _______, and _______.
Three adhesives used for slide attachment are Mayer’s egg albumin, poly-L-lysine, and APES.
The main reagents and steps in a routine H&E stain are: Xylene (_______) → descending alcohols (_______) → hematoxylin (_______) → acid alcohol (_______) → ammonia water (_______) → eosin (_______) → ascending alcohols (_______) → xylene (_______).
The main reagents and steps in a routine H&E stain are: Xylene (deparaffinize) → descending alcohols (hydrate) → hematoxylin (nuclear stain) → acid alcohol (decolorize) → ammonia water (blue nuclei) → eosin (cytoplasm) → ascending alcohols (dehydrate) → xylene (clear).
In H&E staining, nuclei appear _______, cytoplasm appears _______, and muscle fibers appear _______.
In H&E staining, nuclei appear blue–black, cytoplasm appears pale pink, and muscle fibers appear deep pink.
Progressive staining involves applying dye until desired intensity with no _______, while regressive staining involves overstaining then removing excess by _______.
Progressive staining involves applying dye until desired intensity with no decolorization, while regressive staining involves overstaining then removing excess by decolorization.
Two metachromatic stains are _______ and _______, which detect _______.
Two metachromatic stains are toluidine blue and methyl violet, which detect glycosaminoglycans.
Stains that demonstrate lipids in frozen sections include _______, _______, and _______.
Stains that demonstrate lipids in frozen sections include Sudan Black B, Oil Red O, and Sudan IV.
The Feulgen reaction is a specific histochemical stain for _______—it hydrolyzes to expose _______, then Schiff’s reagent binds to yield _______.
The Feulgen reaction is a specific histochemical stain for DNA—it hydrolyzes to expose aldehydes, then Schiff’s reagent binds to yield magenta nuclei.
The gold standard for amyloid detection is _______ which shows _______ under polarized light.
The gold standard for amyloid detection is Alkaline Congo red which shows apple-green birefringence under polarized light.
To demonstrate myelin with Nissl substance, use _______ for myelin plus _______ counterstain for Nissl.
To demonstrate myelin with Nissl substance, use Luxol Fast Blue for myelin plus Cresyl Violet counterstain for Nissl.
Two enzyme histochemistry methods are _______ for alkaline phosphatase and _______ for acid phosphatase.
Two enzyme histochemistry methods are Gomori’s calcium method for alkaline phosphatase and Gomori’s lead method for acid phosphatase.
For rapid fixation of urgent biopsies, the recommended fixative method is _______ heated at _______.
For rapid fixation of urgent biopsies, the recommended fixative method is Formalin heated at 60 °C.
The fixative used for neurochemical substances like acetylcholine is _______ or _______ for EM/histochemistry.
The fixative used for neurochemical substances like acetylcholine is Microwave fixation or 0–4 °C glutaraldehyde for EM/histochemistry.
The silver impregnation stain used for reticulin fibers is _______ (or _______).
The silver impregnation stain used for reticulin fibers is Gomori’s silver impregnation (or Gordon & Sweet’s method).
The stain used for myeloid peroxidase activity is the _______ which turns myeloid granules _______.
The stain used for myeloid peroxidase activity is the Peroxidase reaction which turns myeloid granules green to dark blue.
The best stain for detecting _______ is the _______ (or _______).
The best stain for detecting Helicobacter pylori is the Warthin-Starry silver stain (or Gimenez method).
The metallic impregnation method used for astrocytes is _______.
The metallic impregnation method used for astrocytes is Cajal’s gold sublimation.
Three special fixatives and their uses are: _______ for embryos/pituitary/endometrium, _______ for chromosome prep, and _______ for histochemical preservation of glycogen.
Three special fixatives and their uses are: Bouin’s for embryos/pituitary/endometrium, Carnoy’s for chromosome prep, and Newcomer’s for histochemical preservation of glycogen.
The purpose of gelatin infiltration is to stabilize tissue without _______/_______ during frozen sections and enzyme studies.
The purpose of gelatin infiltration is to stabilize tissue without dehydration/clearing during frozen sections and enzyme studies.
The embedding medium that is water-soluble for enzyme histochemistry is _______ (polyethylene glycol).
The embedding medium that is water-soluble for enzyme histochemistry is Carbowax (polyethylene glycol).
The typical steps and alcohol concentrations for tissue dehydration are: _______, usually 1–2 changes at each grade.
The typical steps and alcohol concentrations for tissue dehydration are: 70% → 80% → 90% → 100% ethanol, usually 1–2 changes at each grade.
Three common clearing agents are: _______ (fast, but toxic), _______ (good penetration, slower), and _______ (gentle, carcinogenic).
Three common clearing agents are: Xylene (fast, but toxic), toluene (good penetration, slower), and chloroform (gentle, carcinogenic).
The recommended volume ratio and time for paraffin infiltration in an Autotechnicon is _______ over _______ with constant agitation.
The recommended volume ratio and time for paraffin infiltration in an Autotechnicon is 4 changes of wax over 1 h with constant agitation.
Vacuum infiltration is used to remove air faster, ideal for _______ and _______ specimens.
Vacuum infiltration is used to remove air faster, ideal for urgent biopsies and lungs/brain specimens.
The process that fills tissue cavities and spaces before embedding is _______ with paraffin, celloidin, gelatin, or resin.
The process that fills tissue cavities and spaces before embedding is infiltration/impregnation with paraffin, celloidin, gelatin, or resin.
The steps for gelatin embedding include: _______ for 24 h → _______ for 12 h → fresh _______ cool until solid → _______ for 12–24 h.
The steps for gelatin embedding include: 10% gelatin + 1% phenol for 24 h → 20% gelatin + 1% phenol for 12 h → fresh 20% gelatin + 1% phenol cool until solid → 10% formalin for 12–24 h.
Double embedding involves infiltrating first with _______ then embedding in _______ for fragile tissues.
Double embedding involves infiltrating first with celloidin then embedding in paraffin for fragile tissues.
Three types of embedding molds and their uses are: _______ for routine blocks, _______ for multiple specimens, and _______ for no trimming.
Three types of embedding molds and their uses are: Leuckhart’s brass for routine blocks, compound unit for multiple specimens, and peel-away plastic for no trimming.
To cool a paraffin block to solidify, refrigerate at _______ or immerse the mold in _______.
To cool a paraffin block to solidify, refrigerate at –5 °C or immerse the mold in cold water.
The speed of frozen sectioning in a cryostat is determined by _______ (–5 to –30 °C), freezing agent, and _______.
The speed of frozen sectioning in a cryostat is determined by temperature (–5 to –30 °C), freezing agent, and section thickness.
Four freezing agents are: _______ (ultra-cold, expensive), _______ (rapid, flammable), _______ (–78 °C, slices thicker), and _______ (fast, uneven freeze).
Four freezing agents are: Liquid nitrogen (ultra-cold, expensive), isopentane–LN2 (rapid, flammable), dry ice (–78 °C, slices thicker), and CO₂ gas (fast, uneven freeze).
The principle of decalcification is to remove _______ to soften tissue; agents include _______ (HCl) for speed and _______ (EDTA) for preservation.
The principle of decalcification is to remove mineral salts to soften tissue; agents include acids (HCl) for speed and chelators (EDTA) for preservation.
Formalin pigments can be removed using _______: 70% ethanol + 28% ammonia; _______: H₂O₂ + ammonia; or _______.
Formalin pigments can be removed using Kardasewitsch: 70% ethanol + 28% ammonia; Lillie’s: H₂O₂ + ammonia; or Picric acid.
A mordant is a substance that bridges _______ to tissue (e.g., alum); an accentuator intensifies selectivity/intensity (e.g., _______).
A mordant is a substance that bridges dye to tissue (e.g., alum); an accentuator intensifies selectivity/intensity (e.g., phenol).
The difference between direct and indirect staining is that direct staining involves the dye binding _______, while indirect staining requires a _______ for binding.
The difference between direct and indirect staining is that direct staining involves the dye binding tissue directly, while indirect staining requires a mordant for binding.
The PAS reaction mechanism involves periodic acid oxidizing carbohydrates to _______ → Schiff’s reagent binds aldehydes producing a _______.
The PAS reaction mechanism involves periodic acid oxidizing carbohydrates to aldehydes → Schiff’s reagent binds aldehydes producing a magenta color.
The PAS reaction mechanism involves periodic acid oxidizing carbohydrates to _______.
The PAS reaction mechanism involves periodic acid oxidizing carbohydrates to aldehydes.
In the PAS reaction, Schiff’s reagent binds to _______ producing a _______.
In the PAS reaction, Schiff’s reagent binds to aldehydes producing a magenta color.
The PAS reaction is used to identify carbohydrates by detecting _______.
The PAS reaction is used to identify carbohydrates by detecting aldehydes.
The first step in the PAS reaction is the oxidation of carbohydrates to _______ by periodic acid.
The first step in the PAS reaction is the oxidation of carbohydrates to aldehydes by periodic acid.
The final product of the PAS reaction is a _______ due to the binding of Schiff’s reagent to aldehydes.
The final product of the PAS reaction is a magenta color due to the binding of Schiff’s reagent to aldehydes.
Fixation is the killing, penetration, and hardening of tissues by stabilizing proteins to resist further changes.
The primary goal of fixation is to preserve cells and tissues as close to their living state as possible.
The secondary goals of fixation are to harden tissue for cutting and protect against handling trauma.
The ideal time to perform fixation after tissue removal is 20–30 minutes following interruption of blood supply.
The recommended volume ratio of fixative to tissue for maximum effectiveness is 20 parts fixative to 1 part tissue.
The preferred osmolality for fixatives is slightly hypertonic or isotonic; hypertonic causes cell shrinkage, hypotonic causes swelling.
The recommended fixative for electron microscopy is osmium tetroxide because it preserves lipids and provides excellent ultrastructural detail.
The fixative traditionally used for general histopathology that is tolerant for mailing specimens is 10% neutral buffered formalin.
Two substitutes for paraffin wax are Paraplast (melting point 56–57 °C) and Ester wax (melting point 46–48 °C).
The section thicknesses for paraffin, celloidin, frozen, and ultrathin are: Paraffin: 4–6 µm, Celloidin: 10–15 µm, Frozen: 4 µm, Ultrathin (EM): 0.5 µm.
The bevel, clearance, and wedge angles for a microtome knife are: Bevel: 27–32°, Clearance: 0–15°, Wedge: 14–15°.
Honing grinds off nicks with oil stones using 20–30 strokes, while stropping polishes on leather using 40–120 strokes.
The main reagents and steps in a routine H&E stain are: Xylene (deparaffinize) → descending alcohols (hydrate) → hematoxylin (nuclear stain) → acid alcohol (decolorize) → ammonia water (blue nuclei) → eosin (cytoplasm) → ascending alcohols (dehydrate) → xylene (clear).
In H&E staining, nuclei appear blue–black, cytoplasm appears pale pink, and muscle fibers appear deep pink.
Progressive staining involves applying dye until desired intensity with no decolorization, while regressive staining involves overstaining then removing excess by decolorization.
The Feulgen reaction is a specific histochemical stain for DNA—it hydrolyzes to expose aldehydes, then Schiff’s reagent binds to yield magenta nuclei.
The gold standard for amyloid detection is Alkaline Congo red which shows apple-green birefringence under polarized light.
To demonstrate myelin with Nissl substance, use Luxol Fast Blue for myelin plus Cresyl Violet counterstain for Nissl.
Two enzyme histochemistry methods are Gomori’s calcium method for alkaline phosphatase and Gomori’s lead method for acid phosphatase.
The fixative used for neurochemical substances like acetylcholine is Microwave fixation or 0–4 °C glutaraldehyde for EM/histochemistry.
The silver impregnation stain used for reticulin fibers is Gomori’s silver impregnation (or Gordon & Sweet’s method).
The stain used for myeloid peroxidase activity is the Peroxidase reaction which turns myeloid granules green to dark blue.
The best stain for detecting Helicobacter pylori is the Warthin-Starry silver stain (or Gimenez method).
Three special fixatives and their uses are: Bouin’s for embryos/pituitary/endometrium, Carnoy’s for chromosome prep, and Newcomer’s for histochemical preservation of glycogen.
The purpose of gelatin infiltration is to stabilize tissue without dehydration/clearing during frozen sections and enzyme studies.
The embedding medium that is water-soluble for enzyme histochemistry is Carbowax (polyethylene glycol).
The typical steps and alcohol concentrations for tissue dehydration are: 70% → 80% → 90% → 100% ethanol, usually 1–2 changes at each grade.
Three common clearing agents are: Xylene (fast, but toxic), toluene (good penetration, slower), and chloroform (gentle, carcinogenic).
The recommended volume ratio and time for paraffin infiltration in an Autotechnicon is 4 changes of wax over 1 h with constant agitation.
Vacuum infiltration is used to remove air faster, ideal for urgent biopsies and lungs/brain specimens.
The process that fills tissue cavities and spaces before embedding is infiltration/impregnation with paraffin, celloidin, gelatin, or resin.
The steps for gelatin embedding include: 10% gelatin + 1% phenol for 24 h → 20% gelatin + 1% phenol for 12 h → fresh 20% gelatin + 1% phenol cool until solid → 10% formalin for 12–24 h.
Double embedding involves infiltrating first with celloidin then embedding in paraffin for fragile tissues.
Three types of embedding molds and their uses are: Leuckhart’s brass for routine blocks, compound unit for multiple specimens, and peel-away plastic for no trimming.
The speed of frozen sectioning in a cryostat is determined by temperature (–5 to –30 °C), freezing agent, and section thickness.
Four freezing agents are: Liquid nitrogen (ultra-cold, expensive), isopentane–LN2 (rapid, flammable), dry ice (–78 °C, slices thicker), and CO₂ gas (fast, uneven freeze).
The principle of decalcification is to remove mineral salts to soften tissue; agents include acids (HCl) for speed and chelators (EDTA) for preservation.
Formalin pigments can be removed using Kardasewitsch: 70% ethanol + 28% ammonia; Lillie’s: H₂O₂ + ammonia; or Picric acid.
A mordant is a substance that bridges dye to tissue (e.g., alum); an accentuator intensifies selectivity/intensity (e.g., phenol).
The difference between direct and indirect staining is that direct staining involves the dye binding tissue directly, while indirect staining requires a mordant for binding.
The PAS reaction mechanism involves periodic acid oxidizing carbohydrates to aldehydes → Schiff’s reagent binds aldehydes producing a magenta color.
The final product of the PAS reaction is a magenta color due to the binding of Schiff’s reagent to aldehydes.
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