Lab8_OralCavity Flashcards
What is the difference between the clinical crown and the anatomical crown?
Clinical Crown = Enamel + top of Dentin
Anatomical Crown = Enamel + top of Dentin + Gingiva (cuticle)
What structures are found in the root of the erupted tooth?
From outside → inside:
- Mucogingival Junctions
- Alveolar Bone
- Peridontal Ligament
- Dentin
- Odontoblast
- Pulp
At the bottom of the root → Peridontal Ligament becomes Apical Foramen
What are the layers of the gingiva?
What layer is just oustide the gingiva?
Inside → Outside:
1. Lamina propria
2. Stratum Germinativum
3. Stratum spinosum
Just outside the gingiva → Parakeratin:
- Not composed of dead cells
- Appears eosinophilic
How is the gingiva classified as an epithelium?
Parakeratinized stratified squamous epithelium
What is the composition of dentin?
What is the composition of pulp?
Dentin = similar to bone:
70% hydroxyapatite + 30% organic material which contains collagen type I
Pulp:
- Contains collagent type I and III
- Fibroblast cells
- Blood vessels, lymphatic and nerves
- Lined by odontoblasts
What is the structure of odontoblasts?
Columnar cells with processes running in the dentin called dentin canaliculi
What is Sharpey’s Fibers?
It is the site of insertion of the peridontal ligament into dentin (at the border)
What is the composition of mature vs immature enamel?
Mature enamel:
- 99% inorganic and made of hydrocyapatite crystals
Immature enamel:
70% inorganic material + 30% amolegenin
*Inorganic material goes away in slice processing so not there
What are the layers of the Enamel organ?
Outside → Inside
1. Outer dental Epithelium (ODE) → continuous with stratum germinativum of the skin
2. Stellate Reticulum:
- Wide intercellular spaces are present
- Largest area of the enamel organ
- Stratum Intermedium
- Resembles stratum spinosum of the skin
- Polygonal shaped cells (less space between) - IDE (Ameoblasts)
- Made of ameloblasts
- Continuous with the stratum germinativum of the oral epithelium
- Cells are columnar + rest on BM
- Cells have short processes that project onto the enamel - Enamel
What are the layers of the Esophagus?
Mucosa:
- Epithelium → non-keratinized stratified squamous
- Lamina propria → loose irregular CT with esophageal cardiac glands (mucous in upper and lower third)
- Muscularis mucosa → thin layer of longitudinally oriented smooth muscle
Submucosa:
- Loose irregular CT
- Esophageal glands proper (mucous glands found throughout)
Tunica muscularis:
- Upper thrid = skeletal muscle (voluntary)
- Middle third = skeletal and smooth muscle
- Lower third = smooth muscle (oblique orientation)
Adventitia/Serosa
- Aventitia: dense irregular CT (until esophagus traverses the diaphragm)
- Serosa: tin layer of loose CT covered by a mesothelium (simple squamous epithelium)