Polarity
Polarity is a feature of cells in which their organelles are distributed asymmetrically in the cytoplasm. In these triangular-shaped gland cells, secretory granules are restricted to the apical (upper) regions of the cell while the blue-staining rough endoplasmic reticulum (RER) is present mostly in the basal regions. This segregation reflects the functional properties of the cells. Pancreas 1000x
Gland cells >
Each gland cell seen here is shaped like a pyramid and is clumped with other similar cells into a spherical cluster. Each cell releases its product into a lumen at the apices of the cells. The lumen is continuous with the duct that drains the cluster.
- Gland cell nuclei
Each gland cell seen here is shaped like a pyramid and is clumped with other similar cells into a spherical cluster. Each cell releases its product into a lumen at the apices of the cells. The lumen in continuous with the duct that drains the cluster.
Lumen
Each gland cell seen here is shaped like a pyramid and is clumped with other similar cells into a spherical cluster. Each cell releases its product into a lumen at the apices of the cells. The lumen in continuous with the duct that drains the cluster.
RER >
Rough endoplasmic reticulum is positioned in the basal regions of the cell and is the site of secretory product synthesis. The ribosomes located on the endoplasmic reticulum possess a negative charge and, therefore, are easy to identify because of their affinity for the blue dye, hematoxylin.
Secretory granules >
The secretory product manufactured by the RER is packaged into secretory granules. These granules accumulate in the apex of each cell, adjacent to the lumen into which they will be released. Secretory granules stain pink with eosin and impart a grainy appearance to the apex of these cells.
