Lecture 5 Flashcards
T/F All structures of the oral cavity are either composed of epithelial tissues, develop from epithelia or are closely associated with epithelia
True
What are three basic types of mucosa in the oral cavity?
masticatory, lining, and specialized
Epidermis is a keratinized _________ squamous epithelium
stratified
What is skin thickness determined by?
The number of layers of keratinocytes and the presence/absence of hair
Thick skin is about how many microns thick?
400-600 microns.
Does thick skin have hair? Where is thick skin found?
No hair and is only found on palms and soles
Thin skin is about how many microns thick?
75-100 microns
Does thin skin have hair? Where is thin skin found?
Yes, has hair and covers all of the body except palms and soles
What cells are part of the epidermis?
Keratinocytes, melanocytes, Langerhans cells (dendritic cells), Merkel’s cells (tactile cells)
Which is the most abundant cell in the epithelium?
Keratinocyte
Why are Langerhans cells also called dendritic?
Dendritic means “treelike” and these cells have treelike branches that extend/wrap around keratinocytes
Why do Langerhans cells in the epidermis migrate into the dermis?
To present antigens to T lymphocytes
Why are Merkel’s cells also called tactile cells?
These cells form a sensitive mechanoreceptor from modified epidermal cells that contain sensory neurons
Which cells in the epidermis are part of the mechanical sense of touch?
Merkel’s cells
Stratum lucidum is a transition layer between what two layers of epidermis? This layer is best seen in type of skin?
Between underlying stratum granulosum and overlying stratum corneum. Best seen in the thick skin of palms and soles
What type of muscle is at the core of lips? What is the muscle’s specific name?
Skeletal muscle. Orbicularis oris
What types of glands is the connective tissue of lips surrounded by?
Salivary, mucous, sweat, and sebacious
What three distinct types of stratified squamous epithelia (SSE) cover the lips?
- Keratinized skin with hair and glands
- Keratinized skin without hair or glands
- Non keratinized or regionally parakeratinized epithelium with glands
Which part of the lip can be described as thin keratinized SSE with hair and glands?
Outer most part of the lip (skin of the face)
Which part of the lip has keratinized SSE WITHOUT hair and glands?
The vermillion border
Which part of the lip is nonkeratinized or regionally parakeratinized SSE with glands?
Oral mucosa of the vestibule (inside mouth)
What two kinds of sensory receptors are found in the vermillion border of the lip?
Free nerve ending in the epidermis
Meissner’s Corpuscles in the dermis
What is a Meissner’s Corpuscle?
A free nerve ending wrapped by several cells like a coil
That does the coiled Meisner’s Corpuscle do?
It helps to amplify the sense of touch in the lips like an antenna
What are the fingerlike projetions of dermis that project into the epidermis called?
Papillae
T/F Meissner’s corpuscles are found in the papillae of the dermis.
True
The vermillion border of the lip is red (“vermillion”). Does this mean that its epithelial layer has blood supply?
No. The epithelium is translucent to the underlying vascular dermis
Why is the vermillion zone epithelia translucent?
Because it is thin and keratinized
Why does the vermillion zone tend to dry out?
It lacks salivary glands and has only a few sebaceous glands
What does the mucosa layer of the digestive tract consists of?
Epithelium, lamina propria, and muscularis mucosae
What does the submucosa layer of the digestive tract have inside it?
Loose CT with vessels, nerves, and glands
What two layers is the muscularis externa layer of the digestive tract composed of?
Inner circular layer of smooth muscle
Outer longitudinal layer of smooth muscle
Which layer of the Muscularis externa is circular? Which is longitudinal?
Inner is circular and outer is longitudinal
What is the slippery and shiny outer layer of the digestive tract called?
Serosa or Adventitia
The serosa layer of the digestive tract is only present where relative to the diaphragm?
Below the diaphragm
The oral epithelium is an avascular layer of cells resting on a basal lamina of type _____ collagen
IV
T/F The lamina propria is part of the epithelial layer of the oral mucosa.
FALSE. It underlies the epithelium and it has blood supply
The lamina propria of the oral mucosa is equivalent to what layer of the skin?
Dermis
What are rete ridges?
Epithelial projections that interdigitate down between the dermal papillae of the lamina propria
Density of CT fibers is highest where the mucosa is ______ (most/least) mobile?
least mobile
T/F The lamina propria contains inflammatory cells.
True
What percentage of adults may have sebaceous glands present in the lip and buccal mucosa?
75%
Does the oral mucosa have the muscularis mucosae layer?
No, unlike the mucosa of the Digestive tract that does have this layer.
What are the three GI mucosae?
Intestinal mucosa, oral mucosa, and oral mucoperiosteum
Which of the three GI mucosae have lots of big folds? Which one has few folds?
Intestinal mucosa has lots of big folds. Oral mucosa has few folds
Masticatory mucosa includes which areas of the oral cavity?
Gingiva and hard palate
Which part of the tongue is considered lining mucosa? Which part is specialized?
The lining mucosa is the inferior surface of the tongue. The specialized mucosa is the dorsal (top) side of tongue
How would one describe the permeability of lining mucosa?
Relatively permeable to such things as topical anesthetics, nitroglycerin and sublingual Vitamin B12
Which oral mucosa has rete ridges?
Masticatory mucosa
What are the four layers into which keratinocytes are differentiated in the masticatory mucosa?
Stratum basale Stratum spinosum Stratum granulosum Stratum corneum Mnemonic: Buy Some Green Candy
Parakeratinized cells accumulate a lot of keratin but also keep their nucleus, which becomes small and highly condensed. What is the term for a shrunken nucleus in these cells?
Pyknotic
What are clusters of yellowish sebaceous glands in the oral mucosa called?
Fordyce’s granules
What determines the nature of the keratinocytes?
The underlying CT (dermis or lamina propria)
What are the two types of gingiva?
Attached and free gingiva
What is the attached gingiva attached to?
Attached to the periosteum of the alveolar bone
What is free gingiva found?
It is found at the crest of the alveolus
What is the area at the apex of the free gingiva called?
Gingival Margin (gingival crest)
What is the crevice above the epithelial attachment? What is it lined with?
Gingival sulcus. Sulcular epithelium.
How many basal laminae does junctional epithelium have? Where are these located?
Two basal laminae. One basal lamina is classically located under the basal cells. The other basal lamina adheres to the surface of the tooth.
Where does the internal basal lamina attach?
To the enamel or cementum (in patients with gum recession)
What to epithelial cells attach with to the internal basal lamina?
Hemidesmosomes
T/F Melanocytes are dendritic cells in the basal layer that form desmosomes with keratinocytes.
FALSE. Melanocytes do NOT form desmosomes. They are “dendritic” so they spread their arms/branches around kerotinocytes
Melanocytes are embryologically derived from what cells?
Neural Crest Cells
