26 Questions
What is the purpose of fixation in sample processing for histopathological examination?
To preserve the tissue structure
Which step of sample processing involves removing water from the fixed tissue?
Dehydration
What is the purpose of staining in histopathological sample processing?
To visualize cellular and structural components
After fixation and dehydration, what is the next step in histopathological sample processing?
Embedding
Which process involves cutting the embedded tissue into thin sections for microscopic examination?
Sectioning
What is the primary purpose of light microscopy in histopathology?
To examine tissue structure at a detailed level
Which technique uses antibodies conjugated to a light-sensitive substance to identify specific antigens or proteins in tissue?
Immunohistochemistry
What aspect of tissue do pathologists focus on when examining morphological changes for disease identification?
Organizational structure
Which component is highlighted using special stains in histopathology?
Pathogenic organisms
How does immunohistochemistry aid pathologists in diagnosing diseases?
By highlighting specific antigens or proteins in tissues
Who was credited with adding the fifth cardinal sign of inflammation, which is loss of function?
Virchow
Which historical figure described the process of phagocytosis during inflammation?
Elie Metchnikoff
When did Celcius list the four cardinal features of inflammation, including rubor, tumour, calor, and dolor?
1st century AD
Who established the concept of chemical mediators of inflammation?
Sir Thomas Lewis
What is the main aim of acute inflammation?
To deliver plasma proteins and leukocytes to the site of injury
Which of the following is NOT a vascular event in acute inflammation?
Decreased vascular permeability
What is the main function of neutrophils during acute inflammation?
Phagocytosis and killing of microbes
Which cells are involved in recognizing microbes in inflammation?
Macrophages
Which pathway is NOT involved in the production of mediators of inflammation?
Viral pathway
What is the primary function of chemokines in inflammation?
Act as chemoattractants for specific leukocytes
What is the major difference in the arrangement of cysteine residues in C-X-C chemokines compared to C-C chemokines?
There is one amino acid residue separating the first two conserved cysteine residues in C-X-C chemokines.
Which type of chemokine is relatively specific for lymphocytes?
C chemokines
Which chemokine promotes strong adhesion of monocytes and T cells in its cell surface–bound form?
CX3CL1 (fractalkine)
What is the primary outcome of acute inflammation where fibrous tissue replaces the damaged tissue?
Healing by fibrosis
Which type of inflammation may have central caseation and is associated with tuberculosis, among other conditions?
Chronic granulomatous inflammation
What is a common systemic effect of inflammation characterized by an elevated number of white blood cells?
Leucocytosis
Study Notes
Introduction to Histopathology: Sample Processing and Microscopic Examination
Histopathology is a crucial branch of anatomy and pathology that deals with the examination of tissues at the microscopic level to diagnose and study diseases. This discipline sheds light on the structure, function, and pathology of tissues, organs, and organisms. In this article, we'll delve into the subtopics of histopathology, focusing on sample processing and microscopic examination.
1. Sample Processing
Sample processing involves preparing tissues for histopathological examination, ensuring that the tissue is preserved, fixed, and stained appropriately so that pathologists can study the tissue structure and identify any abnormalities.
- Biopsy: A tissue sample is collected through biopsy in either a surgical or needle form.
- Fixation: The biopsy sample is immersed in a fixative containing formaldehyde, which chemically binds to the proteins in the sample, preserving its structure.
- Dehydration: The fixed tissue is dehydrated using an ascending series of alcohols to remove the water from the sample.
- Embedding: The dehydrated tissue is embedded in paraffin wax or other resins to provide structural support and prevent deformation during further processing.
- Sectioning: The embedded tissue is cut into thin sections using a microtome.
- Staining: The sections are stained with specific dyes to visualize the tissue's cellular and structural components.
2. Microscopic Examination
Microscopic examination is the process of examining the stained tissue sections using a microscope.
- Light microscopy: This is the most common method used in histopathology to examine tissue sections. The tissue is examined under a light microscope, which increases the visible magnification and allows for detailed observation of the tissue structure.
- Immunohistochemistry: This technique uses antibodies to identify specific antigens or proteins in the tissue. The antibodies are conjugated to a light-sensitive substance (e.g., peroxidase or alkaline phosphatase) that forms a colored product upon exposure to a substrate.
- Special stains: These stains are used to highlight specific components of the tissue, such as bacterial or fungal organisms, collagen, or elastic fibers.
3. Interpretation
Pathologists use the microscopic examination to identify morphological changes that are indicative of a disease or disorder. They analyze the tissue structure, cellular organization, and the presence of any pathogens.
- Morphological changes: Pathologists examine the tissue structure and cellular organization to identify any abnormalities.
- Presence of pathogens: Pathologists look for the presence of bacteria, fungi, viruses, or parasites in the tissue.
- Immunohistochemistry: This technique can help identify specific antigens or proteins that are present in the tissue, providing additional diagnostic information.
- Special stains: These stains can help identify specific tissue components, such as collagen, elastic fibers, or pathogenic organisms.
In conclusion, the study of histopathology is essential for understanding the structure, function, and pathology of tissues. By examining tissue samples under a light microscope and utilizing special stains and immunohistochemistry techniques, pathologists can identify abnormalities and make accurate diagnoses, ultimately benefiting patients and the medical community.
Test your knowledge on histopathology with a focus on sample processing and microscopic examination. Learn about biopsy, fixation, staining, light microscopy, immunohistochemistry, and interpretation techniques used by pathologists in diagnosing diseases.
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