33 - GI System I Flashcards
(95 cards)
What are the three types of mucosa found in the oral cavity?
1 - Masticatory mucosa
2 - Lining mucosa
3 - Specialized mucosa
Where is masticatory mucosa found?
In places where abrasive forces are the greatest (chewing)
What areas does this include? (masticatory mucosa)
- Gingiva (gums)
- Palatine raphe (center line)
- Roof of mouth between gums and raphe
What does the epithelium in the masticatory mucosa contain?
An underlying lamina propria that is anchored to a basal lamina
What is found covering the hard palate?
- Mucosa
- Submucosa
Describe the mucosa of the hard palate
- Epithelium is made up of stratified squamous keratinized cells
- You will also find parakeritinized (partially)
- The keratinized superficial layers will be nonviable/dead
Describe the submucosa of the hard palate
Contains two layers of connective tissue
- Anterior layer: adipose
- Posterior layer: minor salivary glands present
What is Burton’s line?
A blue/grey line on the margin of the gingiva that is indicative of LEAD POISONING - this is due to an actual deposition of lead
What is lining mucosa?
The second type of mucosa we listed that lines most of the oral cavity (like your cheeks)
What type of epithelium will you find in lining mucosa of the oral cavity?
Nonkeratinized stratified squamous (may find small islands of parakeratinized)
What are the three strata you will find in lining mucosa of the oral cavity?
- Stratum basale
- Stratum spinosum
- Straum superficiale
What is the function of the submucosa below the lining mucosa?
Connective tissue that anchors the mucosa
What are filiform papillae?
- Specialized mucosa associated with the tongue
- Covers most of the tongue surface
- Accounts for the roughness of the tongue surface
- Consists of conical projections of keratinized epithelium
Do filiform papillae contain taste buds?
NO! This is the only type of papillae that don’t contain any taste buds
What are fungiform papillae?
- Mushroom shaped projections that contain taste buds at their tip
- Consists of stratified squamous epithelium with partial keratinization
- Extensions of the lamina propria
What are circumvallate papillae?
- Largest of the four types of papillae
- Found proximal to the sulcus terminalis (V-shaped area at the back of the tongue)
- Contain taste buds
- Covered by stratified squamous epithelium
What types of secretions come from circumvallate papillae?
Serous gland secretions
What are foliate papillae?
Leaf shaped papilla that are found on the lateral margins of the tongue and are not well developed in humans
- Stratified squamous epithelium
- Contain taste buds
- Glands empty into the moats surrounding papillae
What are the three types of cells that constitute taste buds?
1 - Sensory cells
2 - Supporting cells
3 - Basal cells
Describe a sensory cell of a taste bud
- Contain microvilli on apical domain
- Taste receptors are within plasma membrane of microvilli which bind to “tastants”
What cranial nerves are involved with taste perception?
CN VII, CN IX, CN X (7,9,10, but no 8, even though eight is the “eater”)
How is taste sensory information perceived?
Taste receptors within the plasma membrane of microvilli bind to tastants that pass through the taste pores where they make synaptic contact with cranial nerves VII, IX, or X depending on the location
Describe the supporting cells of the taste buds
- Support the sensory cells by insulating and separating each individual sensory cell
- This helps to avoid “cross talk”
- Supporting cells have microvilli on the apical domain
Describe the basal cells of the taste buds
- Stem cells
- Replenish the sensory and supporting cell populations when they die (every 10 days, so very active)