BOC Study Guide- Fixation (Exam 1)
Questions and Answers Rated A+
What is the primary purpose of fixation in histology?
A) To enhance tissue color
✔✔B) To prevent tissue decomposition and preserve cellular structure
C) To increase tissue flexibility
D) To minimize sample size
Which of the following fixatives is commonly used for preserving cellular detail in tissues?
A) Acetic acid
✔✔B) Formalin
C) Ethanol
D) Glutaraldehyde
What is the ideal concentration of formaldehyde in 10% neutral buffered formalin?
A) 3.7%
B) 10%
✔✔C) 4%
1
,D) 2.5%
How does formalin fix tissue at the molecular level?
A) By dehydrating cells
✔✔B) By cross-linking proteins
C) By dissolving lipids
D) By denaturing enzymes
Why is glutaraldehyde commonly used in electron microscopy?
A) It is less toxic
B) It is inexpensive
✔✔C) It provides better preservation of ultrastructure
D) It evaporates quickly
Which fixative would be best suited for preserving lipid-rich tissues?
A) Acetone
✔✔B) Osmium tetroxide
C) Methanol
2
,D) Ethanol
Which of the following describes the effect of over-fixation on tissue samples?
A) Enhanced staining quality
✔✔B) Reduced flexibility and harder tissues
C) Increased hydration of cells
D) Decreased preservation
How does pH affect tissue fixation in formalin?
A) pH above 10 improves tissue flexibility
B) Acidic pH stabilizes cellular DNA
✔✔C) A neutral pH stabilizes proteins effectively
D) High pH prevents formalin evaporation
Which type of tissue is commonly fixed with Bouin's solution?
A) Muscle tissue
B) Blood cells
✔✔C) Gastrointestinal biopsies
3
, D) Skin
What is the primary role of acetic acid in fixatives?
✔✔A) Preserving nucleic acids
B) Dehydrating cells
C) Strengthening cellular membranes
D) Staining tissue structures
Why should tissues be thoroughly washed after fixation in formalin?
A) To preserve lipids
B) To prevent oxidation
✔✔C) To remove residual formalin and prevent artifacts
D) To enhance flexibility
What effect does fixation have on enzymatic activity in tissues?
A) Enzymatic activity is enhanced
✔✔B) Enzymatic activity is completely halted
C) Enzymes are unaffected by fixation
4
Questions and Answers Rated A+
What is the primary purpose of fixation in histology?
A) To enhance tissue color
✔✔B) To prevent tissue decomposition and preserve cellular structure
C) To increase tissue flexibility
D) To minimize sample size
Which of the following fixatives is commonly used for preserving cellular detail in tissues?
A) Acetic acid
✔✔B) Formalin
C) Ethanol
D) Glutaraldehyde
What is the ideal concentration of formaldehyde in 10% neutral buffered formalin?
A) 3.7%
B) 10%
✔✔C) 4%
1
,D) 2.5%
How does formalin fix tissue at the molecular level?
A) By dehydrating cells
✔✔B) By cross-linking proteins
C) By dissolving lipids
D) By denaturing enzymes
Why is glutaraldehyde commonly used in electron microscopy?
A) It is less toxic
B) It is inexpensive
✔✔C) It provides better preservation of ultrastructure
D) It evaporates quickly
Which fixative would be best suited for preserving lipid-rich tissues?
A) Acetone
✔✔B) Osmium tetroxide
C) Methanol
2
,D) Ethanol
Which of the following describes the effect of over-fixation on tissue samples?
A) Enhanced staining quality
✔✔B) Reduced flexibility and harder tissues
C) Increased hydration of cells
D) Decreased preservation
How does pH affect tissue fixation in formalin?
A) pH above 10 improves tissue flexibility
B) Acidic pH stabilizes cellular DNA
✔✔C) A neutral pH stabilizes proteins effectively
D) High pH prevents formalin evaporation
Which type of tissue is commonly fixed with Bouin's solution?
A) Muscle tissue
B) Blood cells
✔✔C) Gastrointestinal biopsies
3
, D) Skin
What is the primary role of acetic acid in fixatives?
✔✔A) Preserving nucleic acids
B) Dehydrating cells
C) Strengthening cellular membranes
D) Staining tissue structures
Why should tissues be thoroughly washed after fixation in formalin?
A) To preserve lipids
B) To prevent oxidation
✔✔C) To remove residual formalin and prevent artifacts
D) To enhance flexibility
What effect does fixation have on enzymatic activity in tissues?
A) Enzymatic activity is enhanced
✔✔B) Enzymatic activity is completely halted
C) Enzymes are unaffected by fixation
4
