Processing_of_Tissues_for_Histological_Examination.pptx

Processing_of_Tissues_for_Histological_Examination.pptx

1. Processing of Various Tissues for Histological Examination Embedding, Dehydration, Clearing, Infiltration, and Tissue Processing Dr. Jagroop Singh Phd Biochemistry Government Medical College Amritsar

2. Embedding - Definition Embedding is the process of infiltrating tissue specimens with a medium that provides internal support, allowing the tissue to be sectioned into thin slices for microscopic examination.

3. Various Types of Embedding Media 1. Paraffin Wax: The most common medium, providing good support and preservation. 2. Plastic Resins: Used for high-resolution imaging and harder tissues. 3. Agar and Gelatin: Used for embedding smaller and delicate tissues. 4. Celloidin: Used for large tissues and neurological specimens.

4. Embedding Procedure 1. Dehydration: Removing water from the tissue using increasing concentrations of alcohol. 2. Clearing: Replacing alcohol with a substance that is miscible with both alcohol and embedding medium (e.g., xylene). 3. Infiltration: Saturating the tissue with the embedding medium (e.g., paraffin wax). 4. Embedding: Placing the tissue in a mold with the embedding medium and allowing it to solidify.

5. Routine Timing Schedule for Tissue Processing Manual Processing: 1. Dehydration: 70% alcohol (1 hour), 80% alcohol (1 hour), 95% alcohol (1 hour), 100% alcohol (2 hours). 2. Clearing: Xylene (2 changes, 1 hour each). 3. Infiltration: Paraffin wax (3 changes, 1 hour each). Automatic Processing: Programmed schedules vary depending on the tissue type and processor model, typically ranging from 6-12 hours.

6. Components & Principles of Automatic Tissue Processors 1. Reagent Containers: Hold various solutions for dehydration, clearing, and infiltration. 2. Tissue Cassettes: Securely hold tissue samples during processing. 3. Vacuum and Pressure: Enhance the penetration of reagents into tissues. 4. Heating Mechanism: Maintains optimal temperature for paraffin infiltration. 5. Programmable Controls: Allow customization of processing schedules for different tissue types.