FREE HISTOLOGY AND STUDY GAMES ABOUT FIXATIVES

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FREE HISTOLOGY AND STUDY GAMES ABOUT FIXATIVES

EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

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-Guarantee passing score -34 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation Question 1: Because less extraction of cellular elements occurs with this fixative, sectioning of the paraffin-embedded tissue may be slightly more difficult.

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Modified Millonig Formalin Question 2: This is a sufficiently strong acid to hydrolyze nucleic acids. If stains for DNA and RNA are anticipated, any fixative containing this should be avoided.

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Picric Acid Question 3: Recommended especially for the fixation and preservation of phospholipids in tissues?

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Calcium Formalin

Question 4: This fixative is chemically stable and kept at room temperature.

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Formaldehyde

Question 5: This is probably one of the better formaldehyde solutions if one does not wish to prepare the buffered reagent?

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Acetate Formalin Question 6: This is a hypotonic and organic acid. In a dilute form, it is a common household chemical. Vinegar, which has been used for pickling for many years contains about 5% of this.

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Acetic Acid Question 7: Since formaldehyde is not osmotically active, this solution is very hypotonic and may also produce formalin pigment.

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10% Aqueous Formalin Question 8: This is not used alone, but is used in compound fixatives because it is a very powerful protein coagulant and enhances staining by leaving the tissue very receptive to dyes.It's presence in tissue inhibits freezing, so frozen sections are difficult.

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Mercuric Chloride

Question 9: It's name means "bitter" in Greek.

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Picric Acid Question 10: Because of the hazard associated with the use of this chemical, other metals have been tried as substitutes, but only zinc has found any acceptance.

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Mercuric Chloride Question 11: This solution is recommended for routine formalin fixation. It has a pH of approximately 6.8 and it is hypotonic in the buffer ions present?

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10% Neutral Buffered Formalin (NBF)

Question 12: This solution is isotonic exclusive of the formaldehyde, but may produce formalin pigment?

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10% Formalin Saline Question 13: This chemical causes less shrinkage to tissue even though it is hypertonic and not osmotically active. It preserves morphological details so that tissue is life-like. Penetrates rapidly but fixes slowly (up to 7 days).

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Formaldehyde Question 14: This solution is also an aldehyde, but it differs from formaldehyde in that it is a dialdehyde, with one aldehyde group on each end of the molecule?

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Glutaraldehyde Question 15: This solution is a compound fixative, but is categorized with the other formalin fixatives. It is useful as a fixative on tissue processors because in addition to fixation, the dehydrating process is also begun?

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Alcoholic Formalin Question 16: This leaves tissue more receptive to staining than any other fixative reagent?

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Mercuric Chloride Question 17: Even though specimans for electron microscopy are fixed primarily in an aldehyde solution, they are post-fixed in this to ensure preservation of the lipids?

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Osmium Tetroxide Question 18: This chemical is unique in that it is the only substance used in histotechnique both as a fixative ingredient and as a stain?

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Picric Acid

Question 19: Although this has been used widely as a fixative, it is not recommended because the solution becomes acidic after withdrawal from the storage bottle?

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10% Neutralized Formalin Question 20: This additive fixative is not used frequently in the histopathology lab but is primarily used in the fixation of specimans for electron microscopy?

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Osmium Tetroxide Question 21: This is a very corosive chemical and all contact with metallic objects must be avoided if possible?

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Mercuric Chloride Question 22: Recommended only for tissue of the CNS, especially when the Cajal astrocyte procedure is to be performed. This solution is very acidic, lyses RBC, and causes nuclei to give a direct positive Schiff reaction due to the Feulgen hydrolysis during fixation?

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Formalin Ammonium Bromide Question 23: Techniques using Schiff reagent, such as periodic acid-Schiff (PAS) stain, cannot be used on tissue fixed with this solution because false-positive results are obtained.

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Glutaraldehyde Question 24: This solution is isotonic in buffer ions and has a pH of approximately 7.2-7.4. It can be used as a dual purpose fixative, allowing electron microscopy on stored tissue?

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Modified Millonig Formalin Question 25: This is most frequently used for the fixation of speciman's for electron microscopy as it preserves ultra-struture better than any of the aldehydes. It tends to overharden tissue, so fixation should not be prolonged for more than 2 hours.

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Glutaraldehyde