Lecture Notes: The Mouth and Teeth

Overview of the Oral Cavity

• The mouth, also known as the oral or buccal cavity.
• Vestibule: Bounded by cheeks, lips, gums, and teeth.
• Fauces: Opening between the oral cavity and the pharynx.

Anatomy of the Mouth

• Gingiva (Gums): Attached to the lips via frenula.
  • Superior Labial Frenulum: Connects upper lip to gums.
  • Inferior Labial Frenulum: Connects lower lip to gums.
  • Lingual Frenulum: Connects base of tongue to mouth.
• Palate:
  • Hard Palate: Made of bone.
  • Soft Palate: Made of soft tissue; posterior part includes uvula.
• Arches:
  • Palatoglossal Arch: Formed by palatoglossal muscle.
  • Palatopharyngeal Arch: Formed by palatopharyngeal muscle.
• Tonsils: Located in the posterior portion of the oral cavity.

Salivary Glands

• Three main types:
  • Parotid: Largest gland, contributes 25% of secretion (serous secretions, salivary amylase).
  • Submandibular: Contributes 70% of secretions (both mucus and serous cells).
  • Sublingual: Contributes 5% of secretions (dominated by mucus).
• Functions of Saliva:
  • Begins digestion, particularly starch with salivary amylase.
  • Moistens and dissolves food for tasting.
  • Provides bicarbonate ions to buffer acidic foods.
  • Contains lysozyme (antibacterial enzyme).
  • Rinses mouth to help prevent dental caries.

Salivation Control

• Entirely under nervous control.
• Triggered by:
  • Sight, smell, sound, and memory of food.
  • Tongue stimulation.
• Signals originate from cranial nerves VII (Facial) and IX (Glossopharyngeal).
• Sympathetic Nervous System: Can inhibit salivation.

Mumps

• Infectious disease affecting the parotid gland, causing swelling ("chipmunk cheeks").
• Symptoms: Fever, malaise, sore throat, swelling.
• Can lead to sterility in males due to testicular involvement.
• Mumps is rare due to MMR vaccine developed in 1967.
• Resurgence due to decreased immunization rates.