PANCREAS - SLIDE 144 (human)

Again, you will find pink connective tissue septa dividing the gland into lobules.

Comparing the pancreas with the salivary gland, you will note here that:

1.    While the interlobular ducts are obvious, the intralobular ones are not at all clear; and

2.    scattered throughout; the exocrine parenchyma are small, round or oval, somewhat paler "clumps" of cells, the islets of Langerhans (endocrine portion) . These are diagnostic in the identification of pancreas.

The secretory acini are all serous in type, with round nuclei, lavender basal cytoplasm, and pink, granular apical cytoplasm. (These are zymogen granules typical of merocrine secretion. They are precursors of digestive enzymes; which ones?) While observing acini at high power, can you find any centro-acinar cell nuclei? (What do these cells represent?)

Look at the islets with high magnification and note the irregular cords of cells with many capillaries between them. The majority of the islet cells are fairly small and pale staining. These are the beta cells, which secrete insulin. Scattered among them are alpha, C, and D cells which are not distinctively stained with H&E. The alpha cells are known to secrete glucagon. Read about the effects of both insulin and glucagon upon levels of blood glucose.

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