Histotechnic & Interpretation of Histologic Slides

The Basics of Histologydr. Alya Amila Fitrie, M.Kesdr. Lokot Donna LubisDepartment of Histology, Medicine FacultyUniversity of Sumatera UtaraMedan 2010

1Spesific Learning ObjectivesHow to Study the Cell?How to study the cell?Methods to study cells with microscope

HistotechniqueHistology is the study of the microscopic structure of tissueTissue source: Human Animal

Steps in Tissue Processing1. FixationTo preserve tissue architecture, tissue must be first be fixedChemical reagents are used to hold tissue components in their normal places during the subsequent processingThey also prevent tissue from rotting and auto-digestion by leaked lysosomesProtective from microbial attackFixative only preserve protein

1. FixationFixation effect to the processed tissues:

1. Fixation (contd)Things that must be observed in histological tissue fixation is :2. DehidrationAim : Eliminating the water in cells

3. Clearing As wax and resin arent miscible with alcohol either, the alcohol is replaced with an organic substances called xylene and the tissue goes transparent3. Clearing Substances that are used:

4. Impregnation/Embedding

Tools :Histoplate from plastic (casette) and metal plate (mold).L shaped piece of metal (Leuckhart)Arrange 2 pieces of the iron pieces of sheet metal to form a cuboid space;Pour a little liquid paraffin at the edges to prevent leaking;Put the tissue;Pour paraffin enough to cover the whole tissue;Avoid air bubble formation.Spatula for attaching paraffin blocks.Label this tissue identity when blocking.

5. Blocking 6. Sectioning For optimum viewing, the embedded wax block must be sectioned as finely as possibleThe ideal thickness of the section would be no wider than the diameter of the cells (5-7) for light microscopy.Sectioning done by microtome

6. Sectioning placed in slidesThe thinly cut sections of ribbon are placed onto warm water to flatten them outA glass slide is placed towards the thinly ribbon which picks it up from the water

7. Staining7. StainingHematoxylin Eosin (HE)HE Stain

Collagen fiberMicroscopesTypes of microscopesMagnification & ResolutionTo be viewed under a microscope cells must be within the microscopes limit or resolution. The rsolving power of an electron microscope (EM) is around 400x of a light microscope (LM).

Electron Microscope

Terminology in histology observationTerminology in histology observation based on :ReferencesHistology. Tissue Processing. Download from www.jameswatts.co.ukZulham. Bahan kuliah : Dasar-dasar memahami sel dan jaringan. Alberts B et al. 2002. Molecular Biology of the Cell 4th Ed. New York. Garland Science.Young B, Heath JW. Histology A Text and Atlas. 4th Ed.H&E Staining. ABNOVA, http://www.youtube.com/watch?v=2D0rj0m6dVs

Thank you