SIMPLE TUBULAR GLAND
The mucosa of the intestines has millions of small simple tubular glands. They are called intestinal crypts or also Lieberkühn crypts. These tubules are formed by a simple columnar epithelium and goblet cells are found between the columnar epithelial cells (click here to see the goblet cells of the epithelium of the trachea).
Each goblet cell can be classified as an unicellular gland.
Each gland tubule is both its secretory and the excretory portion. The lumen of the tubules is usually empty and therefore unstained.
The glands are slightly curved and for this reason, they are usually not entirely seen in one section, but rather seen as isolated segments of different lengths.
Some of the glands are highlighted, one of them (on the left) is seen entirely in this section.
The covering epithelial cells of the gland are highlighted in dark blue and the lumen of the gland in light blue. Some goblet cells appear highlighted in green.
The connective tissue of the mucosa, also called its lamina propria, is highlighted in orange.
The upper (white, “empty”) area of the figure is the lumen of the intestine.
Each goblet cell can be classified as an unicellular gland.
Each gland tubule is both its secretory and the excretory portion. The lumen of the tubules is usually empty and therefore unstained.
The glands are slightly curved and for this reason, they are usually not entirely seen in one section, but rather seen as isolated segments of different lengths.
Some of the glands are highlighted, one of them (on the left) is seen entirely in this section.
The covering epithelial cells of the gland are highlighted in dark blue and the lumen of the gland in light blue. Some goblet cells appear highlighted in green.
The connective tissue of the mucosa, also called its lamina propria, is highlighted in orange.
The upper (white, “empty”) area of the figure is the lumen of the intestine.
The cells of these glands secrete various products, including mucus. The secretion of these glands is exocytosed into the gland lumen, and then conducted to the intestinal lumen. Mucus is an important component for the lubrication of the intestinal mucosa and of the intestinal content.
