Explains how liver glycogen appears in hepatocytes after PAS staining, with periodic acid oxidising sugars and Schiff's reagent colouring them magenta, and hematoxylin counterstaining the nuclei blue. Describes how to recognise the magenta granules and clumps, why glycogen is often pushed to one side of the cell, and how feeding affects its amount. Compares it with other PAS-positive structures such as mucins and basement membranes, and explains how diastase digestion of a parallel section confirms the glycogen identity.
Inside: 1 section · 1 min
Topic 97 of 127 in the MU Sofia syllabus for Cytology (Dental Medicine, Year 1). The free AceMed note covers it in 1 section, about 107 words (1 min of reading).
In this note
Introduction
Introduction
The slide demonstrates glycogen, a cellular inclusion, in hepatocytes.
Stain
PAS (periodic acid–Schiff): periodic acid oxidises sugar groups to aldehydes, and Schiff's reagent colours them magenta. Nuclei are often counterstained blue with hematoxylin.
How to recognise it
Plates of hepatocytes with magenta granules and clumps in their cytoplasm.
The glycogen is often pushed to one side of each cell, an artefact of fixation.
The amount varies with the animal's feeding.
Don't confuse it with: mucins and basement membranes, which are also PAS-positive. Digesting a parallel section with diastase removes glycogen but not these, which proves the stain is glycogen.
Theory: topics 3 (histochemistry) and 28 (cellular inclusions).
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