Polarity
Polarity is a feature of cells in which their organelles are distributed asymmetrically in the cytoplasm. These triangular-shaped gland cells secrete digestive enzymes contained within secretory granules that are restricted to the apical (upper) regions of the cell. The blue-staining rough endoplasmic reticulum (RER) is the site of synthesis for these proteins and is present mostly in the basal regions. This segregation reflects the functional properties of the cells. Pancreas 1000x
Gland cells >
Each pyramidal-shaped gland cell assembles with other similar cells into a spherical cluster. Each cell releases its product into a central space (lumen) at the apices of the cells. The lumen is continuous with a tubular duct that drains the cluster.
- Gland cell nuclei
Each pyramidal-shaped gland cell assembles with other similar cells into a spherical cluster. Each cell releases its product into a central space (lumen) at the apices of the cells. The lumen is continuous with a tubular duct that drains the cluster.
Lumen
Each pyramidal-shaped gland cell assembles with other similar cells into a spherical cluster. Each cell releases its product into a central space (lumen) at the apices of the cells. The lumen is continuous with a tubular duct that drains the cluster.
RER >
Rough endoplasmic reticulum is mostly restricted to the basal region of the cell where it synthesizes the enzyme secretory products. Ribosomes located on the endoplasmic reticulum possess a negative charge and, therefore, stain with the blue dye, hematoxylin.
Secretory granules >
The secretory product is synthesized by the RER and packaged into secretory granules. These granules accumulate in the apical region of each cell, adjacent to the lumen into which they will be released. These secretory granules stain with eosin, however, in other cells, they may stain with hematoxylin, depending on their contents.
