BOC Fixation Exam - Questions and Answers

BOC Fixation Exam - Questions and Answers When liver tissue is fixed with 2% to 3% glutaraldehyde: A. Glycogen is dissolved B. The penetration rate is very rapid C. A chemical reaction occurs with lipids D. The ultrastructure is preserved A poor fixative is characterized by: A. The absence of shrinking or swelling of tissue B. Inactivation of tissue enzymes C. Slow tissue penetration D. The absence of distortion of dissolution Bouin solution contains all of the following EXCEPT: A. Picric acid B. Absolute alcohol C. 27-40% formaldehyde D. Glacial acetic acid Coagulant fixatives: A. Change the sponge-work of proteins into a mesh-like network B. Produce fewer artifacts than non-coagulant fixatives C. Act very slowly to fix tissues D. Leave protein linkages unaffected The breakdown of tissue by bacterial action is called: A. Autolysis B. Putrefaction C. Denaturation D. Oxidation When ultrastructural preservation is of the utmost importance, the fixative used should have a pH of: A. 6.8 to 7.0 B. 7.2 to 7.4 C. 7.6 to 7.8 D. 8.0 to 8.2 A fixative component that produces a diffuse brownish black pigment is: A. Picric acid B. Osmium tetroxide C. Mercuric chloride D. Acetic acid For the BEST preservation of staining properties during long-term storage, tissues should be stored in: A. Buffered formalin B. 10% formal-saline C. 70% ethanol D. Zamboni solution Ethanol is useful as a fixative because it: A. Crosslinks proteins B. Increases tissue basophilia C. Prevents tissue shrinkage D. Preserves glycogen very well To prevent the formation of formalin pigment in tissues, formalin should be: A. Heated B. Cooled C. Buffered D. Acidified Which of the following fixatives should be used for specimens that may NOT be processed for several days? A. 10% NBF B. Bouin solution C. Helly solution D. Zenker solution A biopsy that was placed in water by mistake is submitted to the lab. This mistake most likely will cause: A. Mushy sections B. Swollen and ruptured cells C. Hardening of the tissue D. No appreciable changes Sections of a breast carcinoma were fixed in a saline solution in the microwave oven. Microscopic examination of H&E stained sections show marked pyknotic, overstained nuclei. The staining results were most likely caused by the: A. Use of saline for fixation B. Solution temperature exceeding 68 degrees C C. Use of plastic containers in the microwave D. Presence of carcinoma in the breast tissue An unknown pigment in a tissue section that can be bleached with a saturated alcoholic solution of picric acid is most likely: A. Melanin pigment B. Formalin pigment C. Hemosiderin D. Mercury pigment The formaldehyde in Helly solution: A. Causes reduction of some chemicals in the solution B. Coagulates and denatures tissue proteins C. Prevents turbidity and precipitate formation D. Eliminates the need for postfixation washing Formaldehyde solutions for routine use are most commonly buffered by: A. Monobasic and dibasic phosphates B. Sodium acetate and acetic acid C. S-collidine and hydrochloric acid D. Sodium barbitol and sodium hydroxide One characteristic of Zamboni fixative is that it: A. Does not stabilize cellular proteins B. May be used for electron microscopy C. Is easily destroyed by tissue fluids D. Must be followed by osmium tetroxide The BEST fixative for blood smears is: A. Bouin solution B. Carnoy solution C. B-5 solution D. Methanol When used as a secondary fixative, osmium tetroxide should be: