The Mouth and Associated Organs

The mouth – oral cavity Mucosal layer

Stratified squamous epithelium Lamina propria

The lips and cheeks Formed from orbicularis oris and buccinator

muscles, respectively

Anatomy of the Mouth

Figure 22.12a

Figure 22.12b

Anatomy of the Mouth

The labial frenulum Connects lips to gum

The palate Forms the roof of the

mouth

The Tongue Interlacing fascicles of skeletal muscle Grips food and repositions it Helps form some consonants Intrinsic muscles – within the tongue Extrinsic muscles – external to the tongue Lingual frenulum

Secures tongue to floor of mouth

The Superior Surface of the Tongue Tongue papillae

Filiform papillae – no taste buds Fungiform papillae Circumvallate papillae

Sulcus terminalis Marks border between mouth and pharynx

Posterior 1/3 of tongue lies in oropharynx Lined with lingual tonsil

Superior Surface of the Tongue

Figure 22.13

The Teeth

Deciduous teeth – 20 teeth First appear at 6 months of age

Permanent teeth – 32 teeth Most erupt by the end of adolescence

The Teeth

Figure 22.14

How many deciduous teeth are there? A) 32 B) 20 C) 18 D) It varies from person to person.

Tooth Structure

Longitudinal section of tooth in alveolus

Figure 22.15

The Salivary Glands Produce saliva Compound tubuloalveolar glands

Parotid glands Parotid duct – parallel to zygomatic arch Contains only serous cells

Submandibular glands Lies along medial surface of mandible

Sublingual glands Lies in floor of oral cavity Contains primarily mucous cells

The Salivary Glands

Figure 22.16

The enzymes in the salivary glands contains enzymes which begin the digestion of carbohydrates, bicarbonate buffer that neutralizes the acids that are produced by oral bacteria and initiate tooth decay and bactericidal enzymes, antiviral substances, antibodies and cyanide compounds which may kill harmful oral microorganisms.

Which of the following is not contained in saliva?

A) enzymes that begin the digestion of proteins

B) bactericidal enzymes C) enzymes that initiate the digestion of

carbohydrates D) bicarbonate buffer

The Pharynx

Oropharynx and laryngopharynx Passages for air and food Lined with stratified squamous epithelium External muscle layer

Consists of superior, middle, and inferior pharyngeal constrictors