Oral Cavity, Teeth, Tongue, Salivary Glands Flashcards
Identify and describe layers
Lips (labia) is a striated muscle
OM- internal mucosal surface
- has lining mucosa
- with thick nonkeratinized stratified squamous epithelium
- with labial salivary glands
V- red vermillion zone
- with thin keratinized stratified squamous epithelium
- transitional between oral mucosa and skin
- lack salivary glands
- underlying CT is rich in sensory innervation & capillaries (gives pink color on the layer)
S- skin
- epidermal & dermal layers
- sweat glands & many hair follicles with sebaceous glands
Types of mucosal tissues in the oral cavity and
its Functions (individually and as a whole)
Oral cavity:
- lined with stratified squamous epithelium (keratinized, partially keratinized, or nonkeratinized)
- shed cells of nonkeratinized straified squamous epithelium [lower portion of gingiva]
- para-keratinized stratified squamous eipthelium (retain their nuclei)[topmost gingiva]
- Types, locations, functions:
-
Masticatory mucosa (keratinized)
- gingiva and hard palate
- lamina propia (underlying CT) rests directly on the periosteum of the underlying bone
- protects from friction from food chewing
-
Lining mucosa (nonkeratinized)
- soft palate, buccal mucosa (cheek), internal mucosal layer of the lips, uvula, oral cavity floor, pharynx (throat)
- overlies a thick submucosa containing salivary glands (secrete continuously to keep the mucosal surface wet & diffuse lymphoid tissue)
- protects where there’s not much abrasion
-
Specialized
- dorsum of the tongue
-
Masticatory mucosa (keratinized)
Functions:
It houses the structures necessary for mastication and speech, which include the teeth, the tongue and associated structures such as the salivary glands.
Most of the oral cavity functions are related to the tongue, especially the tongue’s muscular (mechanical digestion) and sensory abilities (taste)
Canker sores
Canker sores
- Herpes simplex 1 infection on epithelial cells of the oral cavity
- occur when immune defenses are weakened by emotional stress or physical illness allowing the virus present in the local nerves to move into epithelial cells
- are called cold sores or blisters in skin
Identify indicated regions of this tongue
Identify indicated regions of this taste bud
Identify the regions of this histological slide of the taste bud
Taste Pore-
- minute opening of a taste bud on the surface of the oral mucosa
- gustatory hairs of the specialized neuroepithelial gustatory cells project
Describe the 2 lingual papillae present in this histological slide
F- Fungiform papillae
- (looks like a fungi or mushroom :)
- lightly keratinized
Fl- Filiform papillae
- elongated conical shape
- heavily keratinized
Identiy the type of papillae and describe distinctive features
Vallate (or Circumvallate) papillae
- many taste buds (TB) around the sides and
- several small salivary glands (GL) emptying into the cleft or moat
formed by the elevated mucosa surrounding the papilla
Structure and function of tongue
Tongue structure:
- Mass of striated muscle covered by mucosa
- Muscle fibers oriented in all directions (allowing high level of mobility)
- CT between small fascicles of muscles are penetrated by lamina propia
-
lower surface:
- smooth
- typical lining mucosa
-
dorsal surface:
- irregular
- home for hundreds of papillae (anterior 2/3)- innervated by facial nerve (CN VII)
- the last 1/3 portion are the massed lingual tonsils- innervated by glossopharyngeal nerve (CN IX)
- Sulcus terminalis- V-shaped groove that separates papillae and tonsils
Tongue function: manipulate ingested material during mastication and swallowing
4 types of lingual papillae
- Filiform papillae
- thin and numerous
- elongated conical shape
- heavily keratinized (gray & whitish appearance)
- provides a rough surface that facilitates movement of food during chewing
- Fungiform papillae
- less numerous
- mushroom-shaped (from its name fungi :)
- lightly keratinized
- interspersed among filiform papillae
- well-vascularized
- taste buds on surfaces
- Foliate papillae
- consists of several ridges on each side of the tongue, anterior to the sulcus terminalis
- next to each other
- lateral sides are taste buds
- has von ebner glands
- rudimentary in humans, especially in older individuals (representing evolutionary vestiges of similar structures in many other mammals)
- Vallate (or Circumvallate) papillae
- largest papillae (1-3 mm)
- 8-12 vallate papillae are aligned just in front of the terminal sulcus
- Big groove or furrows
- Lateral sides are taste buds
- von Ebner glands- serous salivary glands that empty into grooves surrounding each vallate papillae
Functions and locations of von Ebner glands
Functions:
- Provide continuous flow of fluid over taste buds
- Wash away food particles so that taste buds can receive & process new gustatory stimuli
- Contain lipase that prevents formation of hydrophobic film
Locations:
- Vallate (major portion of taste buds are found here) papillae
- Foliate papillae
Structure and function of taste buds
Taste buds structure:
- Ovoid structures within the stratified epithelium on the tongue’s surface
- Approx. 250 taste buds are present in the lateral surface of vallate papillae, some are present in fungiform and foliate but not the filiform
- Continuously flushed by minor salivary glands
- Has 50-100 cells:
- Gustatory taste cells- half of the cells with 7-10 day life span
- Other cells: supportive cells, immature cells, slowly dividing basal stem cells which give rise to other cells types
- Apical ends->
- Molecules (tastant) dissolved in saliva
- Tastants contact the microvilli through the taste pore
- Tastants then interact with the cell surface taste receptors
- Base rests on basal lamina->
- entered by afferent sensory axons
- afferent axon form synapses with gustatory cells
- Receptor binding->
- Depolarization of gustatory cells
- Stimulates sensory nerve fibers
- BRAIN for processing
- Conscious preception requires olfactory and other sensations
Taste buds function: Samples the general composition of the ingested material
5 categories of Tastants
Prodcued by ion channels:
- Na+ ions (salty)
- H+ ions (acid)
Mediated by G-protein coupled receptors:
- CHO (sweet)
- Alkaloid & toxins (bitter)
- Glutamate & aspartate amino acids (umami)
Identify types of teeth on each quadrant
In adult human, there are 32 permanent teeth arranged in 2 bilaterally summetric arches in the maxillary and mandibular bones.
Each quadrant has 8 teeth:
- incisors (2)
- canine (1)
- premolars (2)
- permanent molars (3)
Primary teeth (deciduous or milk teeth) -
- replaced by 20 permanent teeth
- complete development and begin to erupt about 6 months after birth.
- development of the secondary tooth buds arrests at the “bell stage,” until about 6 years of age, when these teeth begin to erupt as the primary teeth are shed
ID parts of a tooth
Fun fact: Gingival sulcus-> little space between the gingiva and enamel wher food get stuck
Parts of a tooth or molar:
Crown- exposed above the gingiva
Neck- constricted at the gum
Roots- fit firmly into bony sockets
Dental alveoli- bony sockets
Cover the crown & meet at tooth:
Enamel- crown covering
Cementum- roots by a bone tissue
Dentin- calcified material of tooth surrounding the pulp cavity
Pulp cavity- highly vascular, well innervated, consists largely of loose, mesenchymal CT & much ground substances, thin collagen fibers, fibroblasts, mesenchymal stem cells
Root canal- narrowed pulp cavity
Apical foramen- opening for the blood vessels, lymphatic & nerves of pulp cavity
Peridontal ligaments- fibrous CT bundles of collagen fibers inserted into both cementum & alveolar bone
Dentin
Dentin
- calcified tissue harder than bone
- consists of 70% hydroxyapatite (Ca10(PO4)6(OH)2)
- organic matrix
- contains type 1 collagen & proteoglycans
- secreted from the apical ends of the odontoblasts
Odontoblasts
Odontoblasts
- tall polarized cells derived from the cranial neural crest that line the tooth’s pulp cavity
- Mineralization of predentin matrix
- Odontoblasts secrete predentin matrix (collagenous & not mineralized) at the apical end of the cells & along its processes
- Odontoblasts move toward center of the pulp
- The matix that forms around the elongated process eventually mineralizes (hydroxyapatite crystal forming the process)- Dentin
- Odontoblasts processes will lie within a dentinal tubule
- Continue predentin production into adult life reducing size of pulp cavity
- Odontoblast processes is important for maintenance of dentin in adult teeth
Discuss mineralization of predentin matrix
Mineralization of predentin matrix:
- Odontoblasts secrete predentin matrix (collagenous & not mineralized) at the apical end of the cells & along its processes
- Odontoblasts move toward center of the pulp
- The matix that forms around the elongated process eventually mineralizes (hydroxyapatite crystal forming the process)- Dentin
- Odontoblasts processes will lie within a dentinal tubule
Discuss tooth sensitivity
Stimuli (cold, heat, acidic pH) on exposed dentin->
Surface of dentin being stimulated->
Fluid flow at dentinal tubules->
Unmyelinated nerve fibers in pulp cavity gets stimulated->
Tooth sensitivity
Identify
O- Odontoblast
OP- Odontoblast processes
Enamel
Enamel
- hardest component of the human body
- consists of 96% hydroxyapatite (Ca10(PO4)6(OH)2) & ony 2-3% organic material including very few proteins and no collagen
- fluoropatite- more resistant to acidic dissolution caused by microorganisms (fluoride in toothpaste)
- consists of uniform interlocking of columns (enamel rods or prisms) which is crucial for enamekk hardness & resistance to great pressures during mastication
- Formation of enamel rods:
- Ameloblasts are tall polarized cells that are part of specialized epithelium (enamel organs) which secretes matrix for enamel rods
- Apical ends of the ameloblasts face the odontoblasts producing predentines
- Ameloblasts (or Tomes) processes contain numerous secretory granules with the proteins of the enamel matrix
- Secreted matrix undergoes very rapid mineralization
- Amelogenin is the main structural protein of developing enamel guides growth of hydroxyapatite crystals to produce elongating enamel rod
Discuss formation of enamel rods
Formation of enamel rods:
- Ameloblasts are tall polarized cells that are part of specialized epithelium (enamel organs) which secretes matrix for enamel rods
- Apical ends of the ameloblasts face the odontoblasts producing predentines
- Ameloblasts (or Tomes) processes contain numerous secretory granules with the proteins of the enamel matrix
- Secreted matrix undergoes very rapid mineralization
- Amelogenin is the main structural protein of developing enamel guides growth of hydroxyapatite crystals to produce elongating enamel rod
Peridontium
Peridontium
- comprises the structures responsible for maintaining the teeth in the maxillary & manidbular bone
- includes cementum, periodontal ligament, alveolar bone, & gingiva
Cementum
Cementum
- covers dentin of the root
- avascular
- thickest around root tip where cementocytes reside in lacunae with processes in canaliculi
- cementocytes- maintain surrounding matrix & react to stress by gradually remodeling
- Cementoblasts are the cells that produce cementum
Periodontal ligament
Periodontal ligament
- fibrous CT with bundled collagen fibers (Sharpey’s fibers) binding the cementum and alveolar bone
- highly cellular and has rich supply of blood vessels & nerves
- functions:
- sensory
- nutrition
- support
Alveolar bone
Alveolar bone
- lacks typical lamellar pattern of an adult bone but has osteoblasts & osteocytes engaging in continuous remodeling of bony matrix
- periodontal ligament serves as its periosteum
- collagen fiber bundles of the periodontal ligaments penetrate this bone binding it to the cementum
Gingiva
Gingiva
- bound to periosteum of the maxillary and mandibular bone
- gingival sulcus- grooves between the enamel and gingival epithelium
- juntional epithelium- specialized part of the gingival epithelium that is bound to tooth enamel by means of a cuticle
- cuticle- resembles a basal lamina to which the epithelial cells are attached by numerous hemidesmosomes
Identify parts
Identify type of mucosal tissue in the oral cavity and
label the parts indicated with yellow arrows
Lining mucosa – protects where there’s not much abrasion
minor Salivary gland- (compound tubulo-acinar) ->minor since there’s no septum in the capsule
Identify gross anatomy of the oral cavity
Oral Vestibule – gums, lips and cheeks-> boundary is mandibular and maxillary teeth, internal lining of the lips
Oral Cavity Proper ->
- teeth and gingiva [anterior]
- oral pharyngeal isthmus [posterior]
- hard palate and soft palate, uvula (projections)[roof]
Identify gross anatomy of the tongue
Identify type of papillae and describe
Filiform papillae
- Thin and numerous
- elongated conical shape
- heavily keratinized (gray & whitish appearance)
- provides a rough surface that facilitates movement of food during chewing
Identify type of papillae and describe
Fungiform papillae
- less numerous
- mushroom-shaped (from its name fungi :)
- lightly keratinized
- interspersed among filiform papillae
- well-vascularized
- taste buds on surfaces
Identify type of papillae and describe
Foliate papillae
- consists of several ridges on each side of the tongue, anterior to the sulcus terminalis
- next to each other
- lateral sides are taste buds
- has has von ebner glands
- rudimentary in humans, especially in older individuals (representing evolutionary vestiges of similar structures in many other mammals)
Identify type of papillae and describe
Vallate (or Circumvallate) papillae
- largest papillae (1-3 mm)
- 8-12 vallate papillae are aligned just in front of the terminal sulcus
- Big groove or furrows
- Lateral sides are taste buds
- von Ebner glands- serous salivary glands that empty into grooves surrounding each vallate papillae
Identify the parts of this histological slide of tooth
Enamel washed away during processes since its composed of mostly hydroxyapatite (inorganic materials)
Identify parts of this histological slide of tooth
Describe and identify histology of tooth development including
a. The developmental stages
b. Specific cells that form and maintain major tooth structures
We have two sets of teeth:
- deciduous teeth, which are sometimes referred to as primary or baby teeth, and
- permanent teeth, often known as secondary or adult teeth.
Both sets undergo the same developmental process to form, although permanent teeth are formed later than deciduous teeth, since they eventually replace them. Here are the different stages of odontogenesis.
- Bud Stage
- This first stage happens at the eighth week in utero.
- At this time, cells known as dental epithelium bud from a thick band of cells called the dental lamina, which forms inside the upper and lower jaws.
- These cells will eventually evolve to form the tooth germ, which is made up of all the soft tissues necessary to grow a tooth. Reciprocal induction- interaction between oral epithelium and underlying mesenchymal tissue when the tooth develops.
- Cap Stage
- 10 weeks
- During this stage, cells begin to shape the outside layer of the tooth, forming a cap that sits on the rest of the tooth bud. This cap is called the enamel organ because it will later form the cells that produce enamel. The rest of the tooth bud, known as the dental papilla, will make the two interior layers of the tooth: the dentin and the pulp.
- Another sac of cells, called the dental follicle, surrounds both the enamel organ and the dental papilla. This sac contains blood vessels and nerves. By the cap stage, three different structures make up the tooth germ: the enamel organ, the dental papilla and the dental follicle.
- Bell Stage
- 3 months
- At this point, the enamel organ grows into a bell shape, and two events take place.
- First, cells of the enamel organ differentiate, meaning they change functions. Together, these cell groups work to develop the enamel layer of the tooth. Depending on their new function, they will fall into one of four cell groups:
- Inner enamel epithelium
- Outer enamel epithelium
- Stratum intermedium
- Stellate reticulum
- During the second event in this stage, the enamel epithelium folds into the future shape of the tooth crown, and the dental lamina starts to break down.
- First, cells of the enamel organ differentiate, meaning they change functions. Together, these cell groups work to develop the enamel layer of the tooth. Depending on their new function, they will fall into one of four cell groups:
- Crown and Root Formation
- The outer two layers of your teeth, enamel and dentin, form during the crown stage. These cells come from the enamel epithelium and the dental papilla.
- Ameloblast cells are responsible for creating enamel
- Odontoblast cells create dentin.
- The tooth root, made of root dentin and root canals (where dental pulp lives), forms from a combination of three structures: the dental papilla, the dental follicle and another important group of cells known as root sheath.
Identify stage and indicated parts of this histological slide
Identify
- Pulp cavity
- Odontoblasts
- Predentin (less mineralized)
- Dentin
- Enamel (eventually going to erupt)
- Ameloblast (well organized)
- Periodontal ligament
Teeth are constantly producing dentin and constantly being remodeled
List 3 major salivary glands and compare, contrast and identify histology of the three glands including:
Exocrine gland classification, Secretory products and functions, & Distinct characteristics
(See attached picture for details)
Structures
- Ducts
- Secretory units
- Acinar
- Tubular
Functions
- Lubrication and moisture
- Helps chemical digestion
- Protects oral cavity with immunoglobulins
Types
- Parotid
- Submandibular
- Sublingual
Describe the flow of saliva through the ductal system of a salivary gland
Produced from secretory units->
drains to intralobular ducts
- ducts in the lobules:
- intercalated ducts->
- striated ducts->
interlobular duct->
interlobar duct
Identify
intercalated duct
- composed of simple cuboidal epithelium
- lumen is bigger, cell is cuboidal
Identify
striated duct
- presence of striation d/t the infoldings of membrane
- increase surface area to accommodate excess fluid for mitochondria and ion channels
- simple columnar epithelium (bigger than intercalated duct)
Identify
Interlobular** duct**-> simple columnar to stratified columnar epithelium
Identify
Interlobar** duct**-> bigger lumen composed of stratified columnar epithelium
