Tooth, Tongue, Salivary Glands Flashcards
composition of teeth
internal soft tissue (pulp) and 3 calcified tissues: enamel and cementum (surface layer), and dentin (b/w surface layer and pulp)
what are the calcified dental tissues made of?
calcium hydroxyappatite
what is the crown covered by?
enamel
what is the root covered by?
cementum
what is the cervix?
region where the 2 surface materials meet
composition of enamel
highly calcified matrix composed of 2 fibrous high MW glycoproteins - enamelin and amelogen
what is enamel produced by?
ameloblasts during crown formation
why do adults not produce more enamel?
no longer have active ameloblasts
enamel after tooth eruption?
acellular - cannot repair itself
what does dentin surround?
central pulp chamber and pulp (root) canal
composition of dentin
calcified matrix containing collagen fibers
production of dentin
made by odontoblasts, which remain and continue to produce dentin
where are odontoblasts located?
periphery of pulp - send cytoplasmic extensions (odontoblastic processes) into tunnel-like spaces (dentinal tubules) w/i dentin
how is any stimulation of the nerves in the pulp chamber interpreted?
as pain
composition of cementum
collagen-containing calcified matrix
what produces cementum?
cementoblasts
what are cementocytes?
cells that send processes w/i canaliculi towards the periodontal ligament
cellular cementum
apical region of cementum - contains cementocytes within lacunae
acellular cementum
coronal region of cementum - NO cementocytes
where are cementoblasts found?
both cellular and acellular cementum
cementoblast function
continuously produce cementum after tooth eruption to compensate for the decrease in tooth length that results from enamel abrasion
dental pulp composition
- gelatinous CT w/ odontoblasts in the peripheral layer (closest to dentin)
- fibroblasts
- mesenchymal cells
- thin collagen fibers
describe blood supply of dental pulp
richly vascularized
innervation of dental pulp
- sympathetic vasomotor - control blood vessel luminal diamenet
- sensory
periodontal ligament
dental supporting structure - consists of dense irregular CT b/w root cementum and bony alveolus (alveolar bone proper)
collagen fiber arrangement in periodontal ligament
principal fiber bundles - extend from cementum to bone and suspend tooth in its alveolus
function of principal fiber bundles
absorb and counteract chewing forces
describe perfusion and innervation of periodontal ligament
abundant nerve and vascular supply
gingivae epithelium
stratified squamous parakeratinized to keratinized epithelium
composition/arrangement of gingivae
- has dense irregular CT
- collagen arranged in 5 principal fiber bundles
- similar to periodontal ligament
how does gingivae attach to enamel surface?
via hemidesmosomes
alveolar bone composition
- inner layer = cribriform plate
- outer layer of compact bone = cortical plate
- intervening layer of trabecular bone = spongiosa
what is the sulcus terminalis?
V-shaped depression that divides tongue into anterior 2/3 and posterior 1/3
foramen cecum
shallow pit at the end of the apex of the sulcus terminalis
covering of dorsal surface of tongue?
stratified squamous parakeratinized to keratinized epithelium
covering of ventral surface of tongue?
stratified squamous nonkeratinized epithelium
what do both ventral and dorsal surfaces of the tongue have?
lamina propria and submucosa of dense irregular collagenous CT
what constitutes the bulk of lingual tissue?
muscular core
where are lingual papillae located?
dorsal surface of anterior 2/3 of tongue
four types of lingual papillae?
- filiform
- fungiform
- foliate
- circumvallate
filiform papillae
- short and narrow
- highly keratinized
- pointed
- project above the tongue surface
fungiform papillae
- mushroom shaped
- project above tongue surface
- interspersed among filiform papillae
- occasionally have taste buds
foliate papillae
- shallow
- longitudinal furrows
- located on tongue lateral aspect
circumvallate papillae
- large and circular
- each one surrounded by moat-like furrow
- 10-15 total
- distributed in V-pattern just anterior to sulcus terminalis
taste buds
intraepithelial sensory organs - each consisting of 60-80 spindle-shaped cells
four cell types in taste buds
- dark cell = type 1
- light cell = type 2
- intermediate cell = type 3
- basal cell = type 4
average lifespan of cells in taste bud
10 days
proposed relationship of cell types in taste buds
basal cells give rise to dark cells, which become light cells, which turn into intermediate cells, then die
specialization of taste buds
each taste bud specializes in 2 of 4 tastes
salte and sour tastes
due to specific ion channels in cells
bitter and sweet tastes
due to specific membrane receptors
what specific receptors detect bitter substances?
TAS2R
what detects savory tastes? how?
umami - detects carboxylate ion on glutamic acid - monosodium glutamate
what is loss of taste called?
ageusia
what is partial loss of taste called?
dysgeusia
what can cause partial or complete loss of taste?
infections, radiation treatment, chemicals, head injury
function of lingual salivary glands?
minor salivary glands that deliver serous secretion into furrow surrounding each papilla and assist taste buds in perceiving stimuli
what are the glands of von Ebner?
glands that secrete serous fluid with lipases into the groove by cirumvallate papillae
composition of tongue muscular core
- bundles of skeletal muscle fibers which cross each other in 3 planes
- numerous minor salivary glands interspersed
3 paired exocrine glands that make up the salivary glands
parotid, submandibular, and sublingual
parotid gland
- serous acini
- 28 grams
submandibular gland
- serous and mucous acini - mixed
- 7-8 grams
sublingual gland
- mainly mucous with serous demilunes
- 2 grams
functions of salivary glands
make and secrete lysozyme, amylase, lactoferrin, and secretory component for IgA
description of branching of salivary glands
compound tubuloalveolar - may be serous or mixed mucoserous
composition of salivary glands
dense irregular CT capsule surrounds gland
what divides salivary glands into lobes and lobules?
septa containing excretory ducts
approximately how much saliva does an average person produce in a day?
1.5 L/day
why do you not easily get infections when you get cuts in the mouth?
lysozome and lactoferrin in saliva = antibacterials
salivary gland acini description
- serous and mucous cells arranged around a central lumen
- connects to intercalated duct
where does the intercalated duct lead?
into striated, intralobular ducts
what may intercalated duct cells secrete and absorb?
secrete bicarbonate and absorb chloride ions
what may mucous acini have?
serous demilunes
what aids in saliva secretion?
myoepithelial cells near basal lamina
