Oral and Nasal Cavities Laboratory

Pre-Laboratory

Demonstration Slide: Tooth

Note: Located at front of room. Images available in the Pre-Laboratory Discussion for later study on MEdIC WWW server. Also labeled and unlabeled Review Images for Oral and Nasal Cavities are available from the bottom of this page.

In the adult human there are 32 permanent teeth. Identify:

• the crown, neck and root of the tooth,
• enamel covering the crown,
• cementum covering the root.
• dentin located beneath the external layer of enamel or cementum
• Pulp Cavity a space located beneath the dentin (filled with loose connective tissue composed of odontoblasts, fibroblasts and ground substance and containing many nerves and blood vessels.
  

Slide 120, Tongue, monkey

1. Identify the following types of epithelium: stratified squamous, nonkeratinizing, keratinizing, and with parakeratosis. Can you distinguish the surface of the tongue from the under surface? How?
2. Identify the types of papillae present:
   • filiform most numerous, bent conical projections of the epithelium, with the point of the projection directed posteriorly, no taste buds, stratified squamous keratinized epithelium,
   • fungiform isolated among filiform papillae, slightly rounded, elevated structures with connective tissue core with small fingers or papillae of connective tissue projecting into surface epithelium,
   • circumvallate largest papillae, surrounded by deep groove, large connective tissue core, surface rather smooth, numerous taste buds on the lateral surface.
3. Identify serous glands of Ebner which are at the base of the circumvallate papillae and empty into its surrounding groove.
4. Find taste buds in the lateral wall of the circumvallate papillae or in the surface epithelium of the fungiform papillae. Where else would they be commonly found? They appear as pale, oval structures embedded in the stratified squamous epithelium. Find the taste pore into which the microvilli of the supportive and sensory cells project. Identify the columnar cells [sustenacular (supportive) cells and gustatory (sensory cells)] and basal cells. How is the gustatory (sensory) cell in the taste bud different from the olfactory sensory cells? Can you see the nerve fibers in contact with sensory cells? No.
5. Study the arrangement of the striated or skeletal muscle bundles in the tongue. Find the different types of glands present in the tongue.

Slide 23, Anterior part of tongue, Human and Slide 22, Posterior part of tongue, Human

Identify the following:

• the epithelial layer,
• connective tissue layer,
• striated muscle bundles,
• types of glands present.

Review Images for Oral and Nasal Cavities