Lab8_OralCavity

Question 1

What is the difference between the clinical crown and the anatomical crown?

Answer 1

Clinical Crown = Enamel + top of Dentin

Anatomical Crown = Enamel + top of Dentin + Gingiva (cuticle)

Question 2

What structures are found in the root of the erupted tooth?

Answer 2

From outside → inside:
- Mucogingival Junctions
- Alveolar Bone
- Peridontal Ligament
- Dentin
- Odontoblast
- Pulp

At the bottom of the root → Peridontal Ligament becomes Apical Foramen

Question 3

What are the layers of the gingiva?
What layer is just oustide the gingiva?

Answer 3

Inside → Outside:
1. Lamina propria
2. Stratum Germinativum
3. Stratum spinosum

Just outside the gingiva → Parakeratin:
- Not composed of dead cells
- Appears eosinophilic

Question 4

How is the gingiva classified as an epithelium?

Answer 4

Parakeratinized stratified squamous epithelium

Question 5

What is the composition of dentin?
What is the composition of pulp?

Answer 5

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

Question 6

What is the structure of odontoblasts?

Answer 6

Columnar cells with processes running in the dentin called dentin canaliculi

Question 7

What is Sharpey’s Fibers?

Answer 7

It is the site of insertion of the peridontal ligament into dentin (at the border)

Question 8

What is the composition of mature vs immature enamel?

Answer 8

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

Question 9

What are the layers of the Enamel organ?

Answer 9

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

3. Stratum Intermedium
   - Resembles stratum spinosum of the skin
   - Polygonal shaped cells (less space between)
4. 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
5. Enamel

Question 10

What are the layers of the Esophagus?

Answer 10

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)