Types of tissue specimens I. Cytological - smear, scrape, brushing, washing or fine needle aspirate II. Biopsy (Bx
Anatomical Pathology - Lecture 1
- Pathology: a study of disease
- Types of tissue specimens
- Cytological – smear, scrape, brushing, washing or fine needle aspirate
- Biopsy (Bx) – piece of tissue, trephine, punch specimen
- Whole organ – amputation or mastectomy, appendectomy
- Post mortem samples, routine or forensic
- Tissue preparation modes
- Routine paraffin blocks
- Urgent surgical cases – frozen sections
- Enzyme or lipid studies
- Immunohitochemistry (antibody)
- Special tissue studies (kidney, bone, brain)
- Electron microscopy
- Cytology
- In situ hybridization (DNA or RNA)
- Chemical tissue preservation is used to
- Prevents tissue breakdown: autolysis, putrefaction
- Increases firmness for handling
- Retains tissue structure
- Increase permeability for future chemical processing
Chemical tissue preservation works:
- Denatures protein, breaking down autolytic enzymes, unfolding molecules
- Disrupting internal bonds (H+ & 2S-) increasing permeability & leaving molecules to make new links with fixatives and dyes
- Precipitating proteins and preventing loss during subsequent chemical processing