Oral Cavity -- contains structures for ingestion and fragmentation of food, resulting in formation of a bolus of food for swallowing.

Examine a section of a lip (slide 67 and slide 134). The skin on the external surface (with hair) merges into the nonkeratinized, stratified squamous epithelium oral mucosa on the internal surface (Fig. 15-3).

• Note the abundance of skeletal muscle and small salivary glands in the lip.

Examine a section of an adult tooth (slide 129), which is from a decalcified tooth still embedded in the bone of the jaw. The enamel is completely dissolved away, since this is almost completely calcified material, with little organic content. The section is not well-stained, but resembles the diagram in Fig. 15-7. Starting inside the tooth, identify

• Dental pulp (Fig. 15-12),
• Odontoblasts,
• Predentine, and
• Dentine (Figs. 15-12).

On the outer surface of the tooth, identify

• Bone,
• Periodontal membrane or ligament,
• Cementum, dentine, and
• The gingiva (Fig. 15-7b and 15-13).

What type of connective tissue is the periodontal membrane? The dental pulp?

What does the presence of dentine in this decalcified slide tell you about its composition?

What is the significance of the fine parallel lines that can be seen in the predentine?

Does dentine continue to be made in an erupted tooth?

Developing tooth and the tongue.