a-short-review-of-histology

Oral Cavity and Tongue:

The oral cavity and tongue form the first part of the alimentary canal
It is a specialised area and conforms least to the basic structural plan of the gut The oral cavity contains the teeth, the tongue and numerous salivary glands
The oral cavity is lined by a stratified squamous non-keratinising epithelium
In the connective tissue deep to the epithelium there are many small salivary glands whose secretions help to lubricate the bolus of food and initiate the digestive process
Deep to the lamina propria the wall of the mouth is composed of skeletal muscle, cartilage or bone, depending on the location
The tongue is a muscular structure
It is composed of bundles of skeletal muscle fibres which lie in different planes
This allows the tongue a wide range of movements for the manipulation of food, for speech and for other activities
The muscle fibres are enclosed within connective tissue which also supports blood vessels, nerves and many small salivary glands
The tongue is covered in a stratified squamous non-keratinising epithelium
On the superior surface, the epithelium is thick to accommodate the wear and tear associated with the rasping of food
In addition, there are rows of papillae (epithelial projections) which provide a roughened surface to aid rasping
Taste buds are located in the walls of some of the papillae

Questions:

Epithelial Covering of Tongue:

This composite image shows the epithelial covering on the superior (S) and inferior (I) surfaces of the tongue
The tongue and oral cavity are covered with a stratified, squamous non keratinizing epithelium
However, notice that the epithelial covering of the superior surface of the tongue (the surface you lick with) is much thicker than the epithelium found on the inferior surface
Also note the smooth outer surface on the inferior side of the tongue, whereas the superior (licking) side is roughened

Micrograph of Papillae of the Tongue:

This micrograph shows papillae that project from the superior surface of the tongue
The pale ovoid cellular structures in the side wall of the papillae are taste buds