GI tract Flashcards
Outer surface of the lips
epidermis – stratified squamous with thin layer of stratum corneum
Inner surface of the lips
typical epidermis without stratum corneum but thicker and supported by connective tissue similar to the dermis of the skin.
accessory salivary glands
lie beneath the surface of the lips and continuously secrete small amounts of saliva to moisten the epithelial surface
vermillion region
- transition region between the inner and outer regions of the lips
- thin epithelium with underlying blood vessels
- lacks accessory glands and therefore tends to be dry.
describe the hard palate
- bears ridges
- is covered in stratified squamous epithelium with a thin stratum corneum, it is lightly keratinize
- numerous small salivary gland lie within the connective tissue
- lamina propria becomes more dense connective tissue deeper within the palate
lamina propria
support connective tissue beneath the epithelium
mucosa
epithelium + lamina propria
submucosa
connective tissue just beneath the mucosa
root
- attached tightly to bone within the sockets of the jaw by the periodontal membrane
periodontal membrane
very dense connective tissue with collagen fibers that extend into the bone of the jaw on one side and the cementum connecting to the dentine of the roots on the other
crown
- top part of the tooth above the root line
- used for mastication
incisor
crown is sharp to cut off food
molar
crown is broad and ridged to grind food
pulp
- living tissue of teeth
- fills in the central region of the crown and extends into the roots
- contains blood vessels and nerves which enter the pulp through root canals
root canal
- hollow area in the root which houses pulp extending down into it
dentine
- skeletal tissue that forms the root and most of the crown of teeth
- has fine cellular processes continuous with the pulp
compare dentine to bone
similar matrix but more mineralized and harder
enamel
- skeletal tissue that covers the outer surface of the crown
- contains calcium crystals of hydroxyapatite with denser crystalline structure than bone
what type of skeletal tissue has no cell component?
enamel
what is the hardest of the skeletal tissue?
enamel
inner layer of teeth is derived from…
mesoderm
outer layer of teeth is derived from…
ectoderm
What causes embroyonic development of teeth to begin?
ectodermal epithelium begins to grow into the underlying mesenchyme forming a cap-shaped structure called the enamel organ
dermal papilla
- an aggregation of mesenchyme formed within the enamel gland
- will form dentine and pulp
How does dermal papilla form dentine?
- odontoblasts on the outer surface differentiate
enamel gland
- cap shaped structure formed by ingrowth of oral epithelium
- lined by ameloblasts
- secretes enamel to cover the crown
odontoblasts
- produce dentine
- allow calcium to be added/removed from teeth to contribute to the regulation of blood Ca, though to a lesser extent than bone
What do odontoblasts derive from?
mesodermal precursor cells
they develop from mesenchym
ameloblasts
- line the enamel gland
- secrete enamel
What do ameloblasts derive from?
ectoderm
Cause of gingovitis
- bacteria and food collect in the crevice between the gingiva and tooth
- bacteria can easily breach the thin epithelium here and enter the gingival tissue
symptoms of gingavitis
- inflammation
- receding gums
- exposure of more of the tooth to decay
Compare the matrix of bone, dentine, and enamel
- dentine thin extensions of odontoblasts which remain in mature teeth as tiny, parallel tubes tubes. Highly mineralized and harder then bone
- enamel has no cellular component and is even more highly mineralized than hard. it is the hardest skeletal tissue.
Describe tooth development
i. Tooth formation begins when oral epithelium begins to grow into the underlying mesenchyme forming a cap-shaped structure called the enamel organ. The inner surface is lined with ameloblasts. The underlying mesenchyme forms an aggregate within the cup called the dental papilla. Odontoblasts on the outer surface of the dental papilla secrete dentine. This dentine signals ameloblasts to begin enamel production beneath. The enamel organ will be shed during tooth eruption leaving just the enamel with no cellular covering.
type of muscle in mammalian tongue
skeletal muscle with fibers running in different directions
glands in mammalian tongue
- accessory salivary gland derive from epithelium and open to the surface by ducts
- include serous and mucous glands which continuously secrete a small amount of saliva
epithelium of mammalian tongue
stratified, squamous epithelium
types of papillae on tongue
- fungiform
- filiform
- circumvallate
Where on the tongue will you note find papillae?
on the root
filiform papillae
- Keratinized and covering the tongue surface
- Most numerous
- Smallest
fungiform papillae
- mushroom shaped
- Medium sized
- Bear taste buds along their sides within the epithelial layer
- No keratin
circumvallate papillae
- Largest
- Least common
- Contain taste buds
- No keratin
What are the largest papillae
circumvallate
what are the smallest papillae
filiform
what papillae are keratinzed
filiform
what are the most numerous papillae
filiform
what are the most rare papillae
circumvallate
what papillae have taste buds
fungiform
circumvallete
Describe the structure of taste buds
- Contain pores which allow fluid in to come in contact with neuro epithelial cells which will generate chemical-specific sensation which is conducted out of the base by nerve fibers that travel to the brain
- Glands secrete fluid into the spaces between papillae as taste buds can only function in a liquid environment
accessory salivary glands
- under local control
- smaller
- short excretory ducts
- secrete saliva continuously
major salivary glands
- large and compound
- outside of the oral cavity
- under autonomic control
- secrete large amounts under the presence of food
- large excretory ducts
list the major salivary glands
- Parotid
- Sublingual
- Submandibular
product of parotid salivary glands
serous
product of sublingual salivary glands
mucous
product of submandibular salivary glands
serous and mucous
describe the structure of salivary glands
contains complex, intercalated duct system which collects saliva and conducts it out of the gland
septa of the major salivary gland
- Made of connective tissue
- Divide major salivary glands into lobules
- Support blood vessels and large ducts
acini of major salivary glands
- May produce mucus, serous, or both
* Store their product in secretory granules which are secreted into a central intercaled duct
myoepithelial cells of major salivary glands
• surround acinia and demilunes contracting to push saliva through the duct system
intercalated ducts of major salivary glands
• fuse with larger striated ducts
striated ducts of major salivary glands
• composed of columnar epithelium and secrete lysozyme
excretory ducts of major salivary glands
• conduct saliva through the tissue
circular muscle
the inner muscle layer of the upper GI tract
fibers run circumferentially
longitudinal muscle
the outer muscle layer of the upper GI tract
adventitia
connective tissue sheath covering the outer surface of the GI tract where the tract is bound to
muscularis mucosae
thin layer of muscle just below the mucosa of the GI tract that separates the mucosa from underlying submucosa
submucosa
under the mucosa
composed of loose and dense connective tissue, blood vessles, nerve, lymphoid tissue, and glands
serosa
connective tissue sheath when the GI is free within the abdominal cavity
submucosal plexus
atunomic ganglia between the submucosa of the GI tract
myenteric plexus
autonomic ganglia between muscle of the GI tract
epithelial type of esophagus
- Stratified squamous
- Not keratinized
mucosa of esophagus
- Thinner mucosa
- Thin lamina propia
glands of esophagus
- Within the submucosa
- Similar to seromucous salivary glands
- Secrete lubricating liquid