Lecture 23 Flashcards
(42 cards)
what is the core of the lip composed of? what covers it externally?
skeletal muscle (obicularis oris)
skin
describe the composition of the stratified squamous epithelium of the lip and what it lies on top of
An internal poorly keratinized, modified, stratified squamous epithelium lies on a lamina propria with high papillae
Where are the mixed mucous glands and the capillaries of the lip located?
the mixed mucous glands are within the lamina propria
Dermis has a rich plexus of capillaries which are prominent at the free margin of the lip
Describe the mucous membrane lining the oral cavity.
It consists of stratified squamous epithelium, basement membrane, and lamina propria
It lies on a vascular FECT layer
List the three structures derived from the epithelial bud.
Enamel organ
Dental papilla
Dental sac (follicle)
Discriminate between the dental papilla and the enamel organ with regard to their embryonic origin and their derivatives.
Dental papilla: condensation of mesenchyme that gives rise to dentin and pulp
Enamel organ: forms enamel which caps the dental papilla
(Both are embryonically derived from the epithelial bud)
What is the dental lamina?
It is the “internal limb” that is formed when the primordium forms into a bifid structure
(The external limb goes on to separate the lip from the rest of the oral cavity, however the dental lamina goes on to help the teeth form)
State the function of odontoblasts and how they carry out this function (include increment lines
Odontoblasts: form the dentin matrix throughout the life of the tooth and form a single layer of cells lining the pulp cavity
Tome’s dentinal fibers (odontoblastic processes) are cytoplasmic extensions of odondoblasts that lie through the predentin and dentinal layers to the dentin-enamel junction (occupy the denitinal tubules)
(Have increment lines (of ebner and Owen))
State the function of Ameloblasts and how they carry out this function (include Tome’s processes and increment lines)
Ameloblasts: form enamel (covers only the tooth crown) which is the hardest substance in the body
is 96% organic salts, 90% is Calcium phosphate in the form of apatite crystals and 4% organic matter and water
Enamel is laid down in prisms and each prism is formed by one ameloblast
Tomes’ processes are the secreting apical domains that lay down the rods/inner rods of enamel
Increment lines of retzius are periods of rhythmic growth
State the specific organic components that are unique to enamel and what happens to these substances
Specific organic components, rather than collagen, are unique to enamel and are removed after calcification:
amelogenins, and enamelins
State the function of Cementoblasts and how they carry out this function
Cementoblasts: deposit cementum on the dentin of the root from neck to apex
Cementum has coarse collagen fibers (Sharpey’s) in a bone-like calcified matrix
State the function of the peridontal memebrane the 2 diseases that are known to harm it.
Binds cementum to bony socket, allows limited movement, and absorbs pressures of mastication and prevents this pressure from damaging alveolar bone
Diabetes and Scurvy
The peridontal membrane is composed of __ formed from dental sac with , ____, ______, ______, collagen fibers, blood vessels, and nerve fibers
CT
fibroblasts, osteoblasts, cementoblasts
True or False: the Peridontal membrane is highly metabolically active tissue. explain
True
Describe the Shapey’s fibers of the peridontal membrane
It’s Sharpey’s fibers extend from cementum to alveolar wall
What is the sulcus terminalis?
A structure that separates the anterior 2/3rds of the upper oral portion of the tongue from the posterior portion of the tongue
(4 types of lingual papillae)
Describe the Filiform papillae
Filiform papillae: lack tastes buds and are evenly distributed over the entire oral upper portion
Most numerous of all papillae with a conical appearance
(4 types of lingual papillae)
Describe the Fungiform papillae
Fungiform papillae: interspersed singly among the parallel rows of filiform papillae and are relatively few in number
Have a mushroom appearance and tastes buds are present only on the oral surface of the epithelium in contradistinction to the position of the taste buds on the circumvallate papillae (those are primarily on the lateral walls)
(4 types of lingual papillae)
Describe the Foliate papillae
Foliate papillae: rudimentary in humans and the pharyngeal portion is free of papillae (it contains the lingual tonsils)
(4 types of lingual papillae)
Describe the Circumvallate papillae
Circumvallate papillae: located along the sulcus terminalis as projections surrounded by a moat (circular furrow)
Taste buds present on the lateral walls
Ducts of von Ebner’s glands (serous) open into the moat
State the 2 types of taste cells and where each of them are derived from (describe the “support cell”)
Sustentacular cells and Taste cells
both derived from a single stem cell
Sustentacular cells: spindle-shaped support cells and arrange like barrel-staves to surround the inner taste pore at the base
Describe Taste cells in terms of it’s nucleus, the “outer taste pore”, apical structures, basal portion function, and their distribution in relation to sustentacular cells
Taste cells: each cell is long and slender with an elongated central nucleus and terminates as a short taste hair which projects into the external opening (outer taste pore)
Have apical microvilli with taste receptors
Basal part of cell releasees neurotransmitters
Taste cells are distributed between the supporting cells
Put the following layers of the gut tube in order beginning with the innermost layer
Muscularis externa
mucosa
submucosa
outermost layer
Mucosa (composed of epithelium, lamina propria, and muscularis mucosae)
submucosa
muscularis externa (composed of an inner circular layer and an outer longitudinal layer)
outermost layer (composed of serosa and adventitia)
What type of epithelium can be found in the mucosa?
stratified squamous transitioning to simple columnar
