52 Questions
What is the primary objective of tissue fixation?
To preserve the cells and tissue components as close to normal as possible
How does fixative typically protect a sample from damage?
By disabling intrinsic biomolecules that would otherwise damage the sample
What is the purpose of the additional processing steps and final analyses that are planned?
To determine the appropriate fixation method to use
How does heat fixation differ from other fixation methods?
It preserves overall morphology but not internal structures
What is the effect of prolonged fixation on immunohistochemistry analysis?
It chemically masks the protein targets, preventing antibody binding
What is the purpose of mixing the sample with water or physiological saline in heat fixation?
To evenly spread out the sample for fixation
Which of the following is the most common staining technique used in routine histological analysis?
Hematoxylin and eosin (H&E) stain
What is the primary function of the counterstain in a staining procedure?
To differentiate between different cellular structures
Which of the following is a characteristic of the Leishman stain?
It stains the nuclei blue and the cytoplasm pink
What is the primary purpose of staining biological tissues for microscopic examination?
To highlight specific cellular components or structures
Which of the following factors can influence the intensity of staining in a tissue section?
The concentration of the target tissue
Which of the following is a characteristic of an artifact in a microscopic tissue preparation?
It is a distortion or alteration caused by the preparation process
Which of the following is a primary component of the Leishman stain?
Methylene blue
What is the primary function of the fixative used in tissue preparation?
To preserve the morphological structure of the tissue
Which of the following is a characteristic of natural dyes used in tissue staining?
They are rarely used in modern histological techniques
What is the primary purpose of using a counterstain in a tissue preparation?
To differentiate between different cellular structures
What is the primary purpose of the fixation process in tissue preparation?
To stabilize the proteins, nucleic acids, and microsubstances of the tissue in a state as close to living tissue as possible
Which factor is least important in determining the effectiveness of chemical fixation?
The type of microscopy technique to be used for analysis
What is the purpose of the clearing step in tissue processing?
To replace the ethanol in the tissue sample with an organic solvent miscible with both alcohol and the embedding medium
Which of the following statements is true regarding the embedding process in tissue preparation?
The embedding medium provides support and prevents distortion of the tissue during sectioning
What is the typical thickness range of tissue sections cut for transmission electron microscopy?
0.1-0.5 micrometers (µm)
Which of the following statements is true regarding the mounting of tissue sections?
Sections are floated in a water bath before being mounted onto glass slides
What is the primary advantage of using the freezing method for tissue fixation?
It provides rapid fixation results
Which of the following statements is true regarding the duration of chemical fixation?
A general rule is to allow 1 hour of fixation per 1 millimeter of tissue thickness
What is the purpose of the dehydration step in tissue processing?
To remove water from the tissue and replace it with a series of increasingly concentrated alcohol solutions
Which of the following factors should be considered when selecting the embedding medium for tissue preparation?
The type of tissue and the intended microscopy technique
Fixation is the final step in the process to prepare a sample of biological material for microscopy analysis.
False
Fixatives are non-toxic to common microorganisms like bacteria.
False
The purpose of fixation is solely to increase the mechanical strength of cells and tissues.
False
Heat fixation is commonly used for multicellular organisms like plants.
False
Quick fix using cold formalin for around 24 hours is primarily used in immunohistochemistry to enhance antibody binding.
False
Fixatives do not alter cells or tissues at a molecular level.
False
Leishman stain is mainly used for staining DNA in the cell nucleus.
True
Acidic dyes bind with negatively charged basophilic tissue.
False
Hematoxylin stains RNA-rich portions of the cytoplasm pink.
False
The nuclei take up a pink stain with Leishman stain.
False
Eosin is considered a primary dye in H&E staining.
False
Neutral dyes are commonly extracted from plants and animals.
False
Chelating dyes are used based on tissue geometry.
False
Artifacts can occur due to extraneous factors before fixation only.
False
Natural dyes are mostly petroleum derivatives.
False
Heat fixation is typically used in routine histological analysis.
False
In tissue processing, dehydration removes all water from the tissue by using diluted alcohol solutions.
False
The pH for ultrastructure preservation during fixation should be buffered between 7.2 to 7.4.
True
Hypertonic fixatives result in cell swelling and poor fixation.
False
Embedding for electron microscopy commonly uses paraffin wax as the embedding medium.
False
The thickness of tissue sections cut for light microscopy using a steel knife is typically 5-10 µm.
False
Tissue freezing is a method that provides fine details but does not give rapid results.
False
An ideal thickness for tissue specimens during fixation is between 1-4 cm.
False
Embedding for electron microscopy involves using molds to harden the tissue samples.
False
Chemical fixation occurs within milliseconds and allows preservation of structures in their native state.
True
FFPE tissues can only be stored at low temperatures to prevent degradation.
False
Learn about the purpose and process of tissue fixation in preserving cells and tissue components for microscopy and analysis. Understand how fixatives disable intrinsic biomolecules and protect samples from damage.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
