Anatomical Pathology Flashcards

Foundations of Anatomical Pathology

Introduction

• Anatomical Pathology: A vital field in the analysis of disease through the study of tissues and cells.

• Key Areas: Histopathology and Cytopathology.

Historical Context

• Acknowledgment of Country: Recognition of the traditional custodians of the lands related to knowledge and culture.

Overview of the Anatomical Pathology Laboratory

• Functions:

  • Diagnosis: Surgical pathology, Cytology, Morbid anatomy.

  • Teaching: Available to undergraduates and postgraduates.

  • Research: Focus on cellular and molecular pathology as well as epidemiology.

Histopathology

• Definition: The microscopic examination of tissues to determine disease causes.

• Scope:

  • Diseases Studied: Inflammatory-infectious diseases, immune-related conditions, neoplastic diseases (both benign and malignant).

• Role of a Medical Scientist:

  • Process and prepare tissues for microscopic examination.

  • Apply various techniques for accurate diagnosis.

Overview of Routine Histopathology Procedures

• Steps in Histopathology:

  1. Specimen Reception: Proper handling upon receipt.

  2. Fixation: Preserves tissue integrity.

  3. Processing: Remove water, prepare for microtomy.

  4. Microtomy: Thinly slicing the tissue.

  5. Staining: Prepares tissue for microscopic observation.

  6. Reporting: Provides guidelines for patient management based on microscopic findings.

Importance of Fixation in Histopathology

• What is Fixation?: A method to preserve tissue structure by preventing autolysis and bacterial decomposition.

  • Mechanisms of Action:

  • Arresting enzymatic processes.

  • Inactivating infectious agents.

• Factors Affecting Fixation:

  • Temperature, Size of specimen, pH, and Duration.

• Ideal Fixatives: Should mimic the natural state of the tissue without introducing artifacts.

Microtomy: Tissue Sectioning

• Purpose: To prepare thin tissue sections for staining.

  • Typical Thickness: Ranges between 1-10 µm for light microscopy.

• Tools Used: Various rotary microtomes for precise cuts.

Staining Techniques in Histopathology

• The Role of Staining: Enhances contrast in tissue sections, allowing identification of different cell types and structures.

• Mechanisms by which Dyes Work:

  • Ionic bonding, hydrogen bonding, Van der Waals forces, and covalent interactions.

• Common Dyes Used:

  • Hematoxylin and Eosin (H & E): Hematoxylin stains nuclei (blue), while eosin stains cytoplasm and extracellular structures (pink).

Diagnostic Cytology

• Definition: The study of cell morphology to detect abnormalities, including malignancies.

• Methods of Specimen Collection:

  • Exfoliative: Passive shedding of cells from epithelial surfaces.

  • Abrasive: Manual collection (scraping, brushing).

  • Fine Needle Aspiration (FNA): Minimally invasive sampling from internal organs.

• Advantages:

  • Rapid collection, non-invasive, and cost-effective.

• Limitations:

  • Limited information compared to tissue biopsies and risk of inadequate samples.

Questions to Consider for Understanding

1. What are the main functions and procedures of a histopathology laboratory?

2. Why is fixation critical for tissue processing?

3. Describe the differences in specimen collection techniques for cytology.

Conclusion

• Understanding Anatomical Pathology is essential for accurate diagnosis and treatment of diseases.

  • Requires a combination of technical skills, knowledge of biological processes, and strict adherence to ethical guidelines.