Histology - Oral Mucosas & Salivary Glands Flashcards
(104 cards)
1
Q
What is the vestibule in the oral cavity?
A
It is a horseshoe-shaped space in between your lips/cheeks and teeth/gums.
2
Q
Very first part of the digestive system
A
Oral cavity (within the arches of the teeth)
3
Q
Type of tissue that makes up the skin of the mouth?
A
Epidermis and dermis
4
Q
What type of tissue makes up the inside of our mouth (oral cavity)?
A
Mucosa
5
Q
Specific name of the lip border?
A
Vermillion border of the lip
6
Q
3 types of mucosas of the oral cavity & their embryological tissue origin
A
Masticatory mucosa (ectoderm)
Specialized mucosa (endoderm)
Oral mucosa proper (ectoderm)
7
Q
Mucosa is made up of…
A
epithelium & lamina propria
8
Q
Mucosa of the gingiva (gums) and hard palate
A
Masticatory mucosa
9
Q
Mucosa of the dorsal tongue
A
Specialized mucosa
10
Q
Mucosa of the lining of the mouth (cheeks, ventral tongue)
A
Oral mucosa proper
11
Q
What layer lies directly underneath the mucosa?
A
submucosa
12
Q
Define the submucosa
A
- Layer immediately beneath the mucosa.
- Connective tissue containing collagen, minor salivary glands, adipose tissue, blood vessels, lymphatics, adipocytes
13
Q
Two types of submucosa in the oral cavity and where.
A
Dense: gingiva
Loose: oral/lining mucosa
14
Q
What type of epithelium makes up the oral cavity?
A
Stratified squamous (non-keratinized)
cells in the top layer are alive, have a nucleus
15
Q
Gingivitis
A
Inflammation of the gums
16
Q
The epithelium of of the gums is…
A
para-keratinized (partially keratinized)
17
Q
What is noticeable about the transition between the vermillion border and vestibule?
A
In the vestibule, the epithelium is marked by protrusions of connective tissue called papillae.
18
Q
What is the purpose of papillae in the epithelium of the vestible?
A
They bring blood vessels closer to the border of the epithelium (since epithelia are not vascularized) - supply nutrients to the avascular epithelium.
19
Q
What is the name of the epithelium that runs along the root of the tooth?
A
Junctional epithelium (attaches your gums to your tooth)
20
Q
Describe how the basal lamina reflects to form the attachment between the epithelium and tooth surface?
A
The external basal lamina reflects to form an internal basal lamina that forms an attachment with the tooth enamel.
21
Q
The direct interface between the tooth enamel and junctional epithelium is a modified…
A
basal lamina (internal basal lamina)
22
Q
What purges the crevice between the gingiva and tooth enamel of bacteria?
A
Epithelial cell renewal (between the internal and external basal lamina) with exudate.
23
Q
What is the name of the crevice between the internal and external basal lamina of the junctional epithelium around teeth?
A
Gingival sulcus
24
Q
What causes the basal lamina to reflect onto itself and form the external and internal basal lamina?
A
Tooth eruption in early childhood.
25
The gingiva begins at the...
muco-gingival junction
26
Describe the epithelium of the gingiva
Masticatory epithelium, para-keratinized (partially keratinized, cells retain nuclei and some organelles)
27
The gingiva attaches to the tooth via ... epithelium
junctional epithelium
28
Gingiva can be subject to 2 diseases
* gingivitis (inflammation)
* periodontal disease (periodontitis - more advanced form of infection)
29
Describe the epithelium of the hard and soft palate
Masticatory mucosa, parakeratinized (same as gingiva)
30
The epithelium of the palate reflects to become...
the respiratory epithelium (around the soft elastic palate and uvula)
31
All of the mouth compartments contain minor...
salivary glands
32
Describe the ventral (bottom) tongue lining
Oral mucosa proper (like your cheeks)
33
Which tongue mucosa is thicker?
a) ventral
b) dorsal
b) dorsal
34
The tongue can be separated into 2 sections...
body (anterior 2/3)
base (posterior 1/3)
35
The division between the body and base of the tongue is called...
sulcus terminalis
36
What part of the tongue house the tonsils?
Base
37
Food can get lodged in tonsils due to the presence of...
crypts and pores
38
What is the foramen ceacum?
An epithelial invagination at the base of the tongue - embryological remnant from the process of forming the thyroid gland.
39
The thyroglossal duct remnant can fill with liquid and form...
thyroglossal fistulas and cysts
40
Name the 2 muscles in the tongue
Intrinsic muscle
Extrinsic muscle
41
On the dorsal side of the tongue, there are 4 types of...
specialized lingual papillae
42
Minor salivary glands are also called...
von Ebner's glands
*In the mouth only!*
43
What is the most abundant type of lingual papillae?
Filiform lingual papillae
44
Filiform lingual papillae perceive...
tactile sensation
45
Filiform papillae are arranged in... and inclined...
arranged in V-shaped rows
inclined posteriorly
46
Are filiform lingual papillae keratinized?
They have variable degrees of keratinization. The papillae are keratinized on the sides!
47
What is the shape of filiform lingual papillae?
Cup-shaped
48
Fungiform lingual papillae are mostly located at...
the tip of the tongue
49
Fungiform papillae contain ... at their tip
taste bud cells
50
Describe the shape of fungiform papillae
The are large and rounded
51
Fungiform papillae consist of primary and secondary connective tissue papillae. Describe them.
The core of the papillae is the lamina propria, called primary connective tissue papillae.
The primary CT papillae branch out into smaller interdigitations called secondary CT papillae.
52
What gives rise to the bright red appearance of fungiform lingual papillae?
The interdigitations formed by secondary CT papillae bring blood vessels in the lamina propria very close to the surface of epithelium, which gives rise to the red colour.
53
Name the papillae present near the sulcus terminalis
Circumvallate lingual papillae
54
Circumvallate papillae form a...
lingual "V"
55
Circumvallate are characterized by...
crypts with taste buds
56
At the base of the circumvallate crypts are...
glands (von Ebner's) (they secrete saliva and wash out the crypts)
57
Lingual papillae only present in children (4th type)
Foliate lingual papillae
58
Where are the foliate lingual papillae located? Describe them.
Located on the posterior lateral sides of the tongue.
They form folds and contain taste buds.
59
What are the 4 types on lingual papillae (tongue)
Filiform lingual papillae
Fungiform lingual papillae
Circumvallate lingual papillae
Foliate lingual papillae (children only)
60
5 primary taste sensations
bitter
sweet
sour
salty
umami
61
Each taste bud specializes in ...
2 out of 5 tastes
62
Food particles can bind taste buds via...
taste pores
63
Name the 4 cell types that make up taste buds
1. Sustentacular supporting cells (contains secretory granules)
2. Neuroepithelial cells
3. Intermediate cells
4. Basal, dividing stem cells
64
Taste buds transduce taste sensations via...
sensory afferent nerves
65
At the level of the taste pores, the taste bud cells have ...
large microvilli with taste receptors and ion channels
66
The medical term for taste loss is...
ageusia (or hypogeusia)
67
Potential causes of ageusia (taste loss) (8)
aging
pregnancy
menopause
xerostomia (dry mouth)
radiotherapy
chemotherapy
crushed or cut nerves
zinc deficiency
68
Bitter, sweet and umami tastes are detected by what type of receptor?
What about sour?
What about salt?
Bitter, sweet, umami: G protein-coupled membrane receptors
Sour: Proton (H+) channels
Salt: Sodium channels
69
Epithelial invaginations are extremely important. Some will eventually form your...
teeth
vestibule
70
Glands (in general) derive from epithelium (ectoderm or endoderm) as...
invaginations
71
The invagination of a future gland develops a lumen and divides into 2 portions...
1. secretory portion
2. duct portion
72
What is the difference between exocrine and endocrine glands?
Exocrine glands: have ducts, secrete to the surface of exterior compartments, have local effects
Endocrine glands: do not have ducts, secrete to CT and to the blood, have systemic effects
73
Name examples of exocrine and endocrine glands
Exocrine: salivary glands, pancreas
Endocrine glands: thryoid, parathyroid, adrenal
74
Exocrine glands mostly secrete...
Endocrine glands mostly secrete...
Exocrine glands mostly secrete ENZYMES
Endocrine glands mostly secrete HORMONES
75
Describe the 3 steps of gland development
1. The epithelium invaginates into the underlying connective tissue, bringing the basal lamina with it.
2. The invagination develops a lumen that communicates with the original surface.
3. The invagination differentiates into a secretory unit and a duct which connects it to the epthelium.
76
Exocrine glands can be classified based on the shape of their secretory unit. Name & describe the 3 classes. provide examples.
1. Tubular:
* Secretory unit and duct have a uniform diameter
* Examples: Sweat gland
2. Acinar:
* Grape-like unit attached to a duct
* Example: Salivary gland
3. Alveolar:
* Flask-shaped secretory unit
77
Describe the difference between a simple and compound exocrine gland. Name examples of each.
Simple: One secretory unit is connected to one duct.
Example: sweat gland
Compound: A branching tree-like duct system with multiple secretory units at the ends of each branch.
Example: salivary gland
78
Classification based on manner of secretion:
Define holocrine glands
Holocrine: The entire cell disintegrates to release its secretion (e.g. sebaceous glands of the hair)
79
Classification based on manner of secretion:
Define merocrine glands
Merocrine: Secretory granules are exocytosed without damage to the cell (e.g. salivary glands).
*There is no loss of cell material as the membrane is derived from the Golgi apparatus and fuses back with the cell membrane after releasing its contents.*
80
Classification based on manner of secretion:
Define apocrine glands
Apocrine: A portion of the cell's cytoplasm is shed with the secretion (e.g. matrix vesicles chondrocytes)
81
Classification based on manner of secretion:
Define cytocrine glands
Cytocrine: One cell transfers secretory granules to another via phagocytosis (e.g. melanosome transfer in skin).
82
Name the 4 gland classes based on the manner of secretion. Which type do salivary glands fall under?
Holocrine
Merocrine
Apocrine
Cytocrine
83
Name the 3 gland classes based on the type of secretion product. Define them and give examples.
1. Mucous: Secretion is high in carbohydrates, mucin (50% carbs, 50% proteins).
2. Serous: Watery secretion, with enzyme glycoproteins
3. Mixed: Composed of both serous and mucous cells OR mucous with serous demilunes
84
How much saliva is produced in a day?
1 litre per day!
85
Name some of the functions of saliva (10)
1. protection of teeth and mucosa
2. Lubrication (speech, swallowing)
3. Cleansing/washing
4. Moistening and adhesion of food to make bolus
5. Antibacterial properties
6. Digestion
7. Taste by dissolving food
8. Buffering capacity
9. Remineralization of caries lesions
10. Wound healing
86
Is saliva mainly produced by serous or mucous glands?
Mostly serous glands
87
Name the 3 types of ducts
1. Intercalated ducts
2. Striated ducts
3. Collecting ducts
88
Describe intercalated ducts
Smallest ducts, lined by simple squamous epithelium. Only slightly bigger than capillaries.
Diameter is smaller than the acini.
89
Describe striated ducts
Same diameter as acini. Lined by columnar or high cuboidal cells.
Cytoplasm is eosinophilic and striated due to infoldings and elongated mitochondria.
90
Describe collecting ducts
Largest ducts. Not striated. Lined by simple epithelium (cuboidal or columnar).
*It usually joins the epithelium where the secretion takes place, and tends to resemble that epithelium.*
91
What is primary and secondary saliva? How do they differ?
Primary saliva: Produced by acini, isotonic
Secondary salvia: Modified by ducts, hypotonic
92
Von Ebner glands under the circumvallate papillae in the tongue are an example of...
minor salivary glands
93
Name 3 major salivary glands
Parotid gland
Submandibular gland
Sublingual gland
94
Intralobular vs interlobular ducts
Intralobular: Smaller ducts (striated and intercalated), in lobules
Interlobular: Larger ducts, surrounded by connective tissue
95
Describe the parotid gland
* Largest salivary gland
* Mostly serous
* High amylase enzyme production
* Stenson’s duct opens near the upper 2nd molar, on the inside of the cheek
* Becomes infiltrated by adipocytes with age
96
Describe the submandibular gland
* Produces the most saliva, with 90% serous and 10% mucous acini
* Wharton's duct opens under the tongue
* Long intercalated ducts
97
Describe the sublingual gland
* Smallest gland
* Mostly mucous with serous demilunes
* Produces 5-10% of saliva
* Rivinus' ducts (pl.) open on the floor of the mouth
98
Describe sialoliths
* Sialoliths are salivary gland/duct stones.
* They occur most frequently in the submandibular gland and its duct system.
* The typically contain calcium-phosphate (hydroxyapatite) and proteins
* May require surgical removal
99
What is ectodermal dysplasia?
Group of rare genetic disorders affecting the development of ectoderm derived tissues (everything goes wrong with epithelial invaginations)
100
What is the most common type of ectodermal dysplasia?
Hypohidrotic ED (affects development of sweat glands, teeth, hair and skin)
101
What mutations cause ectodermal dysplasia?
Mutations in ectodysplasin-A receptor
102
Symptoms and effects of ectodermal dysplasia (8)
* Inability to sweat
* Dry fragile skin
* No tears
* No saliva
* No hair
* Abnormal nails
* No mucous glands
* Abnormal teeth
103
What is Sjogren's syndrome?
An autoimmune disorder that attacks exocrine glands, primarily the salivary and lacrimal glands, leading to dry mouth (xerostomia) and dry eyes.
104
What are some consequences of xerostomia and dry eyes in Sjogren's syndrome?
* Rampant tooth decay
* Oral fungal infections
* Corneal opaqueness, loss of vision
* Difficulty eating, swallowing and speaking
