Oral cavity Flashcards

1
Q

Which organs and glands are associated with the digestive tract?

A
  • Oral cavity
  • Pharinge
  • Esophague
  • Stomach
  • Small and large intestines
  • Rectum
    Associated glands:
  • Salivary glands
  • Liver
  • Pancreas
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2
Q

Where does the 1st step of digestion occur?

A

1st step of digestion occurs in the mouth food is moistened by saliva + grounded by the teeth + saliva initiates digestion of carbohydrates

*Food doesn’t stay in the mouth long enough for complete digestion of carbs

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3
Q

What includes the oral mucose (which lines the oral cavity)?

A
  1. nonkeratinized stratified squamous epithelium (resting on BM, squamous but do contian a nucleus)
  2. Lamina Propria of loose CT → very vascular
    *LP is continuous with a submucosa of denser CT containing diffuse small salivary glands (serous, mucous or mixed)

*Oral mucosa covers entire inside of the mouth except gingiva and dorsal surface of the tongue, which are specialized mucosae

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4
Q

Which epitheliums are keratinized or not in the oral cavity?

A

Oral cavity in general → nonkeratinized
Lip → transition from nonkeratinied to keratinized (orthokeratinized)
Gingiva → parakeratinized (wet keratin → tougher because food can be abrasive)

*In general skin has orthokeratin

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5
Q

What is the general structure of the tongue?
(classify the epithelium)

A

Mass of striated skeletal muscle covered by a layer of oral mucosa:
- Mucosa = nonkeratinized (partially keratinized) stratified squamous epithelium
- Lamina propria is strongly attached to the muscles
- Muscle fibers are seen in all different planes of section
- Dorsal surface is irreghular due to presence of papillae

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6
Q

What are the 3 types of papillae found on the tongue?

A
  1. Filiform papilla
  2. Fungiform papilla
  3. Circumvallate papilla
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7
Q

What are the characteristics/structure of the gingiva?
Where to the oral mucosa and gingiva meet?

A

Gingiva has stratum germinativum + stratum spinosum → flattens and becomes keratinized (cells don’t die) → retain nucleus until they desquamate Stains eosinophilic
- parakeratinized
- submucosa CT of gingiva and hard palate is directly continuous with periosteum lining the alveolar bone (doesn’t move freely over the bone)

Oral mucosa and gingiva meet at invisible line called the mucoginginval junction

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8
Q

Which 5 tastes are detected by the taste buds?

A

Sweet, bitter, umami, sour, salt
*All taste buds detect all tastes

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9
Q

What characterizes the filiform papillae?

A
  • Most numerous
  • keratinized on the tip
  • conical shape
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10
Q

What characterizes fungiform papillae?

A
  • small red dots (appear red because the capillaries come very close to surface)
  • more numerous on sides and tip of the tongue
  • small mushroom shaped
  • not keratinized
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11
Q

What characterizes Foliate papillae?

A
  • Mostly in posterolateral portions of the tongue
  • taste buds only present in newbrorn
  • These papillae degenerate very fast, not found in adults
  • Von Ebner’s gland empty into. the base of the furrow
    *No need to identify
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12
Q

What characterizes Circumvallate papillae?

A
  • 8-12 of them form the lingual V (separates anterior 2/3 from posterior 1/3)
  • Large structures surrounded by deep crypts
  • Small particles dissolved by saliva enter lateral walls/cryps → numerous taste buds in the epithelium
  • Von Ebner Gland found are the bottom of each groove/wall → produce aqueous secretion to flush food particles and allow other ones to come in (replace fluid in the crypts)
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13
Q

What are the charactieristics of Von Ebner Glands?

A

*Minor salivary glands
- Serous acini
- Secretion of lipase
- Active in the stomach
*In the circumvallate papillae, they allow to flush food particles from the grooves to allow new tastes to be detected

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14
Q

Which cells are found in taste buds?

A

1 taste bud = 1 pore + 50-60 cells
- Basal cells → Type IV (shorter, stem cells)
- Sensory (pale) cells → Type II most abundant
- Supporting (dark) cells → Type I
- Type III (intermediate) cells

*Nonkeratinized epithelium has small openings (pores)
→ Life-span of 7-10d for all → basal cells divide to give rise to new cells
→ Sensory cells (II) have microvilli (neuroepithelial cells) and depolarize when in contact with food → AP through afferent fibers → many synapse onto 1 Schwann cell

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15
Q

Where do humans have taste buds?
VS the slides in the lab?

A

Humans → Palate, Circumvallate papillae, few in the fungiform papillae

In the lab (animal) → no taste bud in the fungiform papillae, but same for the rest

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16
Q

What are the 3 pairs of salivary glands?
What is the name of their general structure?

A
  1. Parotid gland (mainly serous secretion)
  2. Submandibular gland (Serous + Mucous + Mixed)
  3. Sublingual (mainly mucous secretion)

*ALL COMPOUND ACINAR

17
Q

Which enzymes are produced by salivary glands?

A
  • Amylase → Carbohydrate digestion
  • Lysozyme → destroy bacterial walls
  • IgA → Ab
  • Lactoferrin → uptake iron to prevent virus and bacteria from using it for DNA division
18
Q

What are the 2 types of interlobular ducts?

A

Striated duct (mitochondrias form striations)
Intercalated ducts (smaller, join to )

*Intralobular stained more acidophilic and have not CT around them

19
Q

What are the histological differences (appearance) between Serous and Mucous Acini?

A

Serous Acinus:
- Myoepithelial cells
- Stain darker
- Serous pyramidal cells
- More common(?)

Mucous Acinus:
- NO myoepithelial cells
- Bigger lumen
- Nuclei are compressed to the base of the cells
- Stain palers

*Mixed Acinus = Mucous acinus + Serous Demilune
*Ducts are continuous with branching intralobular ducts to connect to acini to intercalated duct → striated duct → interlobar duct…

20
Q

What are the differences in secretions from Serous vs Mucous cells?

A

Serous cells:
- Thine Proteinaceous secretion (more aqueous)
- Amylase, Lysozyme, Lactoferrin, H2O
- Secretory granules = Zymogenic granules
- Important RER for protein synthesis

Mucous cells:
- Viscous carbohydrate rich product called MUCIN
- secreted when dry mouth in stress conditions

21
Q

What are the general stage of development of the tooth/dental arche?

A
  1. Bud stage
  2. Cap stage early
  3. Cap stage late
  4. Bell stage
22
Q

What are the names of the 2 dental arches in the embryo?

A

Upper → Maxilary dental arche
Lower → Submandibular dental arche

*At embryo stage, all covered by ectoderm

23
Q

What happens in the Bad stage of the dental arche?

A
  1. Neuro-ectoderm cells migrate from neural crest
  2. Neuro-ectoderm cells induce formation of epithelial tooth buds (10 future baby tooth/arche)
    *Migration induces formation of the tooth buds
24
Q

What happens in the cap stage early of the tooth development?

A
  1. Epithelial structure (oral ectoderm) will form the future enamel organ
  2. Migrated neuro-ectoderm cells mix with mesoderm cells (mesenchymal cells) and form the neural crest mesoderm
25
Q

What happens in he Cap stage late of tooth development?

A
  1. The future enamel organ remains connected to the oral ectoderm via the dental lamina + originates a 2nd bud for the permament tooth (side bud)
  2. Cells of the enamel organ differentiate into defined layers (ODE and IDE)
  3. Some cells of the neural crest mesoderm (mostly neuro-ectodermal cells) start differentiating into odontoblasts
26
Q

What happens in the bell stage of tooth development?

A
  1. In addition to IDE and ODE, the enamel organ differentiates into Stratum Intermedium and Stellate Reticulum
  2. IDE is formed of columnar ameloblasts which synthesize enamel
    *CROWN shapes at the Bell stage
  3. Cervical loop marks position of the neck of the tooth → crown-root junction (where the enamel will stop)
  4. Odontoblasts become aligned (under IDE) and primitive dental papilla (future pulp) is formed
    - Mainly mesenchymal cells → transformed into CT cells

*ODE is still connected to the ectoderm by the dental lamina

27
Q

What steps are involved in the root formation of the tooth?

A

ODE nd IDE will eventually disapear (undergo apoptosis) at the level of the root (under Anatomical crown level)
- Odontoblasts remain there (already recruited) → induce mesenchyme to form cementoblasts and cementum

Between the bone and the cementum, Peridontal Ligament is formed (forming tooth is floating within a pocket of Alveolar bone)

*Baby topth function until 5-6 years old

28
Q

What is the dentino-enamel junction?

A

Junction betwneee the IDE and the odontoblasts (end of Enamel)

  • From this point, the odontoblasts grow inwardly
  • IDE does not form Enamel from that point on, it is involved in recruitment of odontoblasts
29
Q

How does the permanent tooth develop?

A

It develops in the same manner (Cap stage, bell stage, etc.) as the baby tooth, but waits for the baby tooth to fall off before to erupted

Odontoclasts (Osteoclasts) erode the root of the baby tooth and the new permanent tooth grows as the rooth of the baby tooth is eroded (at the end, baby tooth only held by the gingiva)

30
Q

What are the Ameloblasts of the IDE continuous with in the root sheath?

A

Ameloblasts continuous with the remaining IDE
- Odontoblasts will line the IDE

31
Q

What starts at the Dentino-enamel junction?

A

Start of the Rooth
End of the Anatomical Crown

32
Q

What are Tome’s processes?
What are Tome’s fibers?

A

Tome’s processes:
- Apical bulging of the ameloblasts into the enamel (secretion of enamel proteins?)

Tome’s fibers:
- Odontoblasts process localted in the dentinal tubule → pre-dentin