Chapter 1 - basic concepts Flashcards
Define histology, pathology (including general and systemic pathology) and histopathology
Histology – the study of microscopic structure of tissues
Pathology – the study of diseases
General pathology - Mechanisms and characteristics of diseases
Systemic Pathology - Diseases involving body physiological systems or
organs
6 Characteristics of disease
- Aetiology (cause)
- Pathogenesis (mechanism)
- Pathological and clinical manifestations (structural and functional features of the disease)
- Complications and sequelae (secondary effects)
- Prognosis (outcome)
- Epidemiology (incidence)
Disease can be classified as congenital (before birth) and acquired (after birth). What are the two congenital classifications and 6 classifications?
Congenital: 1. genetic 2. non-genetic Acquired: 1. inflammatory 2. vascular 3. growth disorders 4. injury and disordered repair 5. metabolic and degenerative disorders 6. disordered immunity
3 steps in the process of diagnosis
- medical history
- physical examination
- lab investigations
8 laboratory disciplines?
- Clinical chemistry
- cytogenetics
- cytopathology
- haematology
- immunology
- microbiology
- histopathology
- molecular diagnostics
4 ways to examine tissues
- direct examination under light microscope
- smear technique
- impression method
- sectional method
What is direct examination used for?
- fresh cells (blood or lymph)
- usually diluted with isotonic solution such as saline - fresh tissue (loose subcutaneous connective tissue)
- direct examination when tissue is thin
- for thicker tissue, cells can be separated in normal saline by dissociating or teasing
what is the smear technique used for?
- fluids containing cells
- blood or bone marrow aspirate
- smear on microscopic glass slide
- adherent cells are fixed to preserve their appearance
- stain the cells and observed under the microscope - Pap smear
- exfoliated cytology
- standard method
what is the impression method used for?
- used for organs such as spleen or bone marrow biopsy
- procedure:
1. Gently pressing the cut surface of the organ onto a slide
2. Preserve a little architectural arrangement of the tissue in the imprint
what is the sectional method used for?
Routinely used for most tissues
• Effective means of studying tissues of the body
• Prepared from fixed tissues
• Cutting tissues into very thin translucent slices/
sections
• Architecture of the tissue is very well preserved
• Sections are usually about one cell thick
What is the process of getting diagnosis usually?
Process:
1. Doctor referred patient to specialist in hospital
2. Surgeon performed biopsy or surgery to remove
suspected tissue/organ
3. Tissue/organ sent to pathology department
4. Pathologist will examine the gross macroscopic view of specimen and select tissue of interest
5. Medical Technologists will process tissue (Histological Techniques)
6. Pathologist will examine the tissue under microscope and provide final diagnosis
What are the 7 steps of histological techniques?
Steps involved:
- Fixation
- Tissue processing
- Embedding
- Microtomy/paraffin sectioning
- Fishing
- Staining
- Microscopic examination