lecture 15/16 Flashcards
oral cavity (GI1)
which organs/tissues are included in the digestive system?
digestive tract:
* oral cavity
* pharinge
* esophagus
* stomach
* small/large intestine
* rectum
associated glands:
* salivary glands
* liver
* pancrease
what is the function of the digestive system?
obtain, from ingested food, the metabolites for growth and energy requirments, and bepfre being stored or used as energy, it must be digested and transformed into small molecules that cna be absorbed through the lining of the GIT
what is the first step of digestion?
- occurs in the mouth
- food is moistened by saliva and ground by the teeth into smaller pieces
- saliva also initiates the digestion of carbohydrates
classify the epithelium lining the oral cavity
nonkeratinized stratified squamous epithelium
what is special about the epithelium on the lips?
a transition from keratinized to nonkeratinized can be seen
is the gingiva keratinized?
it is parakeratinized
is the external lip keratinized?
it is orthokeratinized
the tongue is a mass of _______ muscle covered by a layer of ______
striated; oral muscosa
classify the mucosa of the tongue
nonkeratinized stratified squamous epithelium
why is the dorsal surface of the tongue irregular
b/c of presence of smal eminencies called papillae
what are the different types of papillae?
- filiform
- fungiform
- circumvallate
what type of gland is found near circumvallate papillae?
von ebner gland
what type of gland are von ebner glands?
serous
what do von ebner glands secrete?
lipase, which is active in the stomach
what different cells are seen in a taste bud?
- supporting cells (type I) – are dark
- sensory cells (type II) – are pale
- type III cells (intermediate cells)
- basal cells (type IV) – stem cells
type I and II have micorvilli which cause depolarizaton when coming in contact with food - afferent fibers with schwann cell
what are the different human tase perceptions?
- saltiness
- sweetness
- sourness
- bitterness
- umami
where can we find taste buds?
- palate
- circumvallate papillae
- a couple in fungiform papillae
function of salivary glands
- to wet and lubricate the oral cavity and uts content
- to initiate the digestion of carbohydrates
- to secrete amylase, lysosyme, IgA, and lactoferrin
what are the different types of salivary glands?
also, are they serous or mucous
- parotid (mainly serous)
- submandubular (serous and mucous)
- sublingual (mucous)
what is the shape of salivary glands?
compound acinar
difference between the serous and mucous acini?
- serous: pyrymidal, acidophilic, small lumen, myoepithelial cells, zymogenic granules that secrete thiner proteinaceous secretions
- mucous: bigger, stain pale, nucleus at the base, bigger lumen, prodcue mucin
difference between striated and intercalated ducts?
- striated: have striations (deliniated cells), more organized
- intercalated: generally smaller (nuclei will seem bigger), less organized
diphyodonty
having two sets of teeth
how many baby and adult teeth do we have?
20 baby and 32 adult
