What are the three components of the digestive system?
What are the functions of the oral cavity?
Describe the structure of the lips.
Anterior margin of the oral cavity
External aspect is the skin
Intermediate (Vermillion) transition zone
Internal aspect- 'wet' mucosa- continuous with the internal aspect of the cheeks
Describe the layers of the internal aspect of the lips.
Epl: stratified squamous, non-keratinized
L. Propria: dense, irregular CT
Submucosa: Mucous glands
Adventitia: Skeletal muscle- continuous with gingiva
Transition/Vermillion zone- highly vascularized lamina propria
Describe the external aspect of the lips (skin).
Epl: stratified squamous, keratinized epithelium
Contains hair follicules and hair shafts
What is the function of the gingiva?
Surround and encase roots of teeth
Help protect the periodontal ligament via Junctional Epithelial collar- bacterial barrier which prevents periodontal disease
Describe the layers of the gingiva.
Epl: lightly keratinized stratified squamous epl
L. Propria and Submucosa: dense irregular CT, prominent collagen I fibers which mingle with the periodontal ligament
What are the three sections of the tooth?
Enamel, dentin, and pulp chamber
What is the clinical crown?
All of the tooth above the gum line
What is the anatomical crown?
Everywhere on the tooth where there is enamel on top of the tooth
Describe the enamel of the tooth.
Produced by ameloblasts on outer surface of developing tooth
Enamel is non-vital/non-regenerative
Describe the dentin of the tooth.
Produced by odontoblasts on inner surface of tooth lining pulp chamber
Dentin is vital/regenerative
Innervated/Pain if injured
Describe the pulp chamber of the tooth.
Loose CT; high GAG content, jelly-like
Highly vascularized and innervated
Vessels and nerves enter and exit the pulp chamber via narrow root canal
What is cementum?
Bone-like tissue, but avascular
Produced by cementoblasts
Some remodelling by odontoblasts
Describe the periodontal ligament.
Coll I fibers embed in alveolus/spongy bone and cementum
Highly innervated- pain and proprioception
What is the alveolus of the tooth?
Socket of spongy bone in mandible/maxilla
What is the palate?
roof of the oral cavity
Consists of a hard palate and soft palate
Describe the hard palate.
Epl: Stratified squamous keratinized
Describe the soft palate:
Epl: Stratified, squamous, nonkeratinized
Adventitia: skeletal muscle
Elevates with uvula during swallowing to close nasal cavity entrance to pharynx
Describe the structure of the tongue
Mucosal specializations = papillae with taste buds
Prominent posterior MALT= lingual tonsils
Submucosal serous glands trap tastant molecules
Adventitial intrinsic skeletal muscle manipulates chewed food into a bolus
What are the papillae of the tongue made up of?
Stratified squamous keratinized epithelium with a dense, irregular CT core
Describe the structure of taste buds.
Spindle-shaped sensory receptor cells (I&II)
Have apical microvilli in taste pore on apical surface of epithelium
Tastant chemicals dissolved in serous fluid enter pore and bind to/activate G-coupled cell surface receptors on microvilli- downstream signals stimulate synapse-like release and activation of afferent sensory neurons