a-short-review-of-histology

Accessory Glands of GI Tract:

During development of the gut tube many glands are derived from the basic gut tube which is initially formed
In many parts of the gut tube there are mucous secreting glandular cells which form part of the lining epithelium
These include the single celled glands known as goblet cells
Multicellular glands develop from downgrowths of epithelial cells from the primitive gut lining into the underlying connective tissue of the lamina propria or submucosa of the gut tube
For example, in the mouth and oesophagus there are many small glands whose secretions lubricate and add digestive enzymes to the food
There are also some large glands which lie outside of the gut tube but retain a connection through a duct(s) which carry the secretions into the lumen of the gut tube
These include:

Submandibular, sublingual and parotid glands which drain into the oral cavity. (These will be studied later, during classes on the head and neck)
Liver
Pancreas

Questions:

Goblet Cells:

In the micrograph shown, goblet cells are stained green
The green staining shows the mucus secretion in storage vesicles within the single cell glands knows as goblet cells (so called because their shape is similar to a Paris goblet wine glass)
Look closely on the apical surface of the epithelial cells to identify a thin layer of green stained mucus (derived from goblet cells)
This mucus serves to protect the epithelium
Goblet cells become more numerous in the large intestine, particularly at the distal end

Submucosal Gland:

In this micrograph identify the 3 layers of the mucous membrane of the oesophagus:- epithelium, lamina propria and muscularis mucosae
The area of submucosa (lying deep to the mucous membrane) shown in this micrograph is occupied by a mucus secreting gland
Notice the duct which, in life, would carry the secretions of the gland and deposit them onto the luminal surface of the epithelium