Oral Cavity Lecture Notes

Overview of the Oral Cavity

• The oral cavity is the first part of the digestive system.
• Functions as an entry point for digestion and is crucial for mastication and speech.
• Houses structures like teeth, tongue, and salivary glands.

Key Structures in the Oral Cavity

• Teeth: Important for mastication.
• Tongue: Central organ for taste, chewing, swallowing, and speaking.
• Salivary Glands: Aid in digestion by secreting enzymes.
  • Parotid, submandibular, and sublingual glands.

Anatomy of the Tongue

• Muscular organ attached to the floor of the oral cavity.
• Comprises 8 muscles: 4 intrinsic and 4 extrinsic.
• Covered with mucosa and lingual papillae for taste sensation.
  • Types of papillae: filiform, fungiform, vallatae, and foliate.
  • Filiform papillae have a mechanical role, not for taste.

Tongue Muscles

Intrinsic Muscles

• Superior Longitudinal: Retracts and broadens tongue, elevates apex.
• Inferior Longitudinal: Retracts and broadens tongue, lowers apex.
• Transverse: Narrows and elongates tongue.
• Vertical: Broadens and elongates tongue.

Extrinsic Muscles

• Genioglossus: Depresses and protrudes tongue.
• Hyoglossus: Depresses and retracts tongue.
• Styloglossus: Retracts and elevates lateral tongue.
• Palatoglossus: Elevates root of tongue, constricts isthmus of fauces.

Innervation of the Tongue

• Motor Innervation:
  • All muscles by hypoglossal nerve (CN XII) except palatoglossus (vagus nerve, CN X).
• Sensory Innervation:
  • Posterior third: glossopharyngeal nerve (CN IX).
  • Anterior two-thirds (general): lingual nerve (branch of mandibular nerve, V3).
  • Anterior two-thirds (taste): facial nerve (CN VII).

Oral Cavity Structure

• Anteriorly situated on the face, bounded by a roof, floor, and lateral walls.
• Opens anteriorly to the face via the oral fissure; communicates posteriorly with the oropharynx via the oropharyngeal isthmus.
• Bony framework includes maxillae, palatine, temporal bones, mandible, sphenoid, and hyoid bones.

Additional Information

• Oral Vestibule: Divided into anterior and posterior by dental arches.
• Blood Supply: From the lingual artery, branch of the external carotid artery.

Study Resources

• Videos and quizzes available for detailed learning.
• Interactive study units on tongue anatomy, muscles, and innervation.

Related Topics

• Development of the palate.
• Disorders of the tongue.
• Anatomy and function of various papillae and tongue muscles.
• Neurovasculature of the tongue.