Liver, glycogen storage (PAS stain)
This PAS-stained specimen demonstrates the presence of glycogen (red color) stored in hepatocytes. The distribution of varying concentrations of glycogen can reveal recent nutritional history. Note that in this specimen, glycogen is more densely concentrated in the central region of lobules (around the central veins) than in the periphery (around and between portal areas).
Because sinusoidal blood flows from the periphery toward the center of the lobule, hepatocytes in the periphery respond first to whatever demands are placed upon them by incoming blood. Therefore, glycogen is depleted first from the periphery during times of fasting and deposited first in the periphery during times of feasting.
A similar effect governs hepatocyte damage. Cells in the lobule periphery will be more vulnerable to incoming toxins, while cells in the lobule center will be more vulnerable to hypoxia.
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Last updated: 15 February 2002 / dgk