SalivaΛΒ°πΌπβπ𫧠Flashcards
saliva is a mixture that contains 3 pairs of major salivary glands list them______
parotid gland
submandibular gland
sublingual gland
along the major salivary glands we have other glands situated beneath the oral mucosa________
minor salivary glands
saliva contains other constituents list them
GCF (gingival crevicular fluid ) from gingival sulcus
microbial contaminants ex, bacteria , toxins etc
desquamated epithelial cells which are dead cells from oral mucosa that eventually shed into saliva
saliva composition
mainly water , inorganic, nonprotein organic compounds , and proteins
Ions in saliva Important for Buffering & Remineralization
also K+ and Na+
why is K + more in saliva and less in plasma , Na+ more in plasma and less in saliva
the sodium is actively resorbed by salivary glands as it moves through ducts esp. the striated ducts resulting into more sodium in plasma now for potassium its the opp. salivary glands secrete it into the ducts sooo more in saliva btw this whole exchange is how primary isotonic saliva become final hypotonic saliva(ΛΆΛ α΅ ΛΛΆ)
functions of saliva
lubricates our oral cavity making it easy to swallowβ.α
water balance how?(α΅βα΄β) well ..
(π§ NaβΊ reabsorbed in ducts, π«π§ water stays
π§ͺ Saliva becomes hypotonic (less salty)
π₯΅ Dehydration β β saliva β π dry mouth
π§ Triggers thirst β makes you drink! π₯€
π‘οΈ Helps conserve body water )
antimicrobial action by lysozyme, lactoferrin , IgA and IgG
digestion by amylase which is an enzyme in bacteria
saliva acts as a solvent for chemicals in food this helps stimulating taste receptors π»ββοΈΰΎΰ½²ΰΎΰ½²
minor role in excretion by excreting small amounts of waste ex urea, ammonia and heavy metals
remineralization by forming an acquired enamel pellicle which is protein layer on surface of tooth , ion reservoir , buffer
mechanical cleansing
aggregates and clears away microorganism
lastly saliva contains buffering agents which neutralize acid in plaque ( helps to buffer PH changes in plaque)
why is saliva considered a wonderful biomarker to know if there is a systemic disease
due to its rich mixture of substances
we can know if there is oral cancer , DM and esp. we use saliva to know if there is AIDS also helps in knowing hepatitis B and C ( ΛΆΒ°γ
Β°) !!
minor salivary glands are located where
Labial mucosa (lips)
Buccal mucosa (cheeks)
Tongue (especially the base)
Hard palate (posterior part)
Soft palate
histology of major salivary glands
classified as compound tubuloacinar glands branching network of **ducts **with secretory units clustered at end called **acini **which secrete saliva into **lumen **then saliva moves into intercalated ducts
describe serous secretions
low viscosity and rich in protein
describe mucous secretions
high viscosity and rich in carbohydrates
secretory epithelial cells can form two types of clusters
circular or tubular
secretory epithelial cells sit on what
basement membrane
whatβs the role of the delicate CT that surrounds BM
provides nutrients, blood supply , O2 to epithelial cells
structure of salivary gland
surrounded by capsule where CT septa divides it into lobes where its further divided into lobules where the acini and ducts are
3 types of secretory units
- serous
-mucous - mixed which is mucous with serous demilune ( serous cells that sit on top of mucous acini looking like half moon hence the name demilune)
serous acini histologically
intensely staining cells due to the protein
got a central lumen and basement membrane that is surrounded by delicate CT
mucous acini histologically
pale staining cells cuz of mucin ( glycoproteins with lots of carbohydrates/sugar preventing it from picking up the stain)
nucleus is at the base
got also basement membrane surrounded by delicate CT
mixed acini histology
the main part is tubular cluster of mucous cells and on top is serous demilune where its fine cell processes extend into lumen
serous cells produce what
protein and polysaccharides
mucous cells produce what
mucinogen
if we look inside the serous cell we can see
apex is acidophilic - has dark stained granules ( protein rich vesicles )
basal part is basophilic - basal prominent nucleus
organelles for synthesis of proteins
they will add amylase, some IgA and glycoproteins to saliva
if we look inside mucous cell we can see
basal prominent nucleus
organelles to produce CHO
secretion mainly protein sugar complex called mucin
mucous and seromucous will add some IgA , lysozyme and some lactoferrin
myoepithelial cells role
they are specialized epithelial cells located btw the secretory cells and their BM , octopus like due to their cytoplasmic processes around the acini and intercalated ducts
they expel and contract due to the actin filaments , allows expansion of the acinar cells to store and contract to force it out into lumen
myoepithelial cells under light microscope
spindle shaped nuclei that can obvious but acidophilic cytoplasm tend to blend with CT
ductal system
structure and function depends on the glands whether major or minor
ductal wall made of epithelial cells and type of epithelium varies along
transports , ion and fluid exchange modification of saliva
intercalated duct
short and directly connected to acini
lined by short cuboidal epithelial cells
prominent in parotid gland
join striated duct
both intercalated and striated ducts are what kind of ducts
Intralobular ducts (within a lobule)
striated duct
main ion exchange site
larger than intercalated
low columnar epithelial cells with basal striations
in EM those basal striations look like plasma infoldings filled with mitochondria for NA+/K+ pump
resorbing sodium and secreting K ,bicarbonate and phosphate buffers
if we have low flow rate of saliva
more time for ion exchange so more hypotonic saliva
if we have high flow rate of saliva
less time for ion exchange so isotonic
interlobular excretory ducts
larger than striated
large lumen
near striated pseudostratified columnar sometimes with mucous goblet and as we go towards oral cavity becomes stratified columnar then stratified squamous nonkeratinized epithelium
collects saliva and transport it to oral cavity
main excretory ducts
stratified squamous non keratinized epi
they modify a little not like striated by resorbing Na+ and secreting K+ and mucous
empties into oral cavity
what surrounds the parenchyma (acini and ducts) basically entire salivary gland
CT stroma
what is stroma made of
fibrous CT
includes capsule and septa( branches of CT that divide gland into lobes and lobules)
provides blood supply ,nerve supply and physical support
nerve supply in salivary gland
autonomic ( para and symp)
parasympathetic stimulation
triggered by taste and smell
causes vasodilation( more blood flow into acini and ducts) leading to water serous saliva production
sympathetic stimulation
viscous mucous secretion
why is major salivary glands discontinuous
cuz its stimulated by taste , smell , chewing
parotid gland
serous acini
eosinophilic in H and E stain sections
intralobular adipose tissue
at higher magnification serous cells contain intracellular zymogen granules
submandibular gland
mixed but more serous than mucous
ofc its mucous with serous demilune
got also adipocytes
sublingual gland
mucous
large secretory ducts
also adipocytes
minor salivary glands
over 600
mainly mucous
lack true capsule its circumscribed
( loosely surrounded by CT)
known as accessory glands
architecture of minor salivary glands
small , scattered clusters unlike major glands which are one large encapsulated gland
made of tiny lobules and may share a common excretory ducts or have their own opening into oral cavity
continuous secretion so no need for neural control )βΉ ΰ£ͺ οΉποΉποΉβΉ ΰ£ͺ Λ
embryology of salivary glands
origin: primitive oral ectoderm
invagination: starts in weeks 6-7
bud formation : epithelial buds into underlying mesenchyme then divides and branch forming spherical cells
end of cord : secretory acini
proximal part : duct
CT : capsule and septa develop from surrounding mesenchyme not ectoderm
as we age what changes
less cells
more fibers / CT
more adipocytes
saliva production decreases hence hyposalivation , dental caries , oral diseases
clinical considerations
infections
viral: mumps ( parotid commonly affected)
bacterial due poor hygiene or duct blockage
sialolithiasis ( salivary stones)
tumors of glands
autoimmune diseases: Sjogren syndrome
