CSMLS Histology Fixation Questions with complete solutions.

CSMLS Histology Fixation Questions with complete solutions. The primary purpose of fixation is to: a. stop enzymatic action b. remove the water from the tissue c. provide support for the tissue d. autolyze the tissue - correct answers.a. enzymes are proteins and rendered inactive by fixation Which of the following fixatives contains picric acid, formalin and acetic acid a. Zenker b. Helly c. Bouin d. Zamboni - correct answers.c. Bouin The ratio of fixative to tissue should be a. 1:2 b. 5:10 c.15:20 d. 25:50 - correct answers.c. 15 times to 20 times Tissue must be washed in running water after fixation in: a. Zenker solution b. absolute alcohol c. glyoxal d. formalin - correct answers.a. a pigment may be formed when tissue is taken from a chromate-containing solution directly into alcoholic solution Which of the following fixatives contains formalin, potassium dichromate and mercuric chloride a. Zenker b. Helly c. Carnoy d. Orth - correct answers.b. Helly Precipitate left in tissues that have been fixed in solutions containing mercuric chloride may be removed by immersion in: a. running water b. sodium thiosulfate c. weak ammonia water d. iodine - correct answers.d. either Gram or Lugol iodine Commercial stock formaldehyde solutions contain: a. 4% formaldehyde b. 10% formaldehyde c. 37% to 40% formaldehyde d. 98% to 100% formaldehyde - correct answers.c. 37% to 40 % formaldehyde; diluted 1:10 for use Formalin pigment would most certainly be formed when the pH of the formalin is: a. 5.0 b. 6.0 c. 7.0 d. 8.0 - correct answers.a. 5.0. While it is likely to happen with a pH of 6.0 it would most certainly happen with pH of 5.0 Formalin pigment may be removed from tissue by a. running water b. alcoholic iodine c. alcoholic picric acid d. potassium permanganate - correct answers.c. alcoholic picric acid 10% formalin is the same as: a. 3 7% to 40% formaldehyde b. 10% formaldehyde c. 4% formaldehyde d. 1% formaldehyde - correct answers.c. 10% formalin is a 1:10 dilution of 37% to 4% formaldehyde; therefore a 10% solution is the same as 3.7-4 % formaldehyde For best results when using formalin as a routine fixative, it must be made