LEC57: Salivary glands & Exocrine pancreas Flashcards
what kind of glands are salivary
exocrine
what kind of glands are pancreas glands
exocrine & endocrine
what are salivary & pancreas glands assoc w/?
both functionally & structurally, assoc w/ digestive system
how do exocrine glands release secretory product
via a duct onto external surface / into lumen of an organ
ie intestine
how do endocrine glands release their hormone
into blood circulation or tissue space
both exocrine and endocrine glands begin how
epithelial cell downgrowth into CT
major salivary glands
parotid
submanidbular
sublingual
produce ~90% totaly volume of saliva
minor salivary glands
lips
tongue
palates
~10% total volume of saliva
identify the major salivary glands
what does saliva contain?
how much/day?
water, ions, mucins, antimicrobial substances, IgA, enzymes, proteins
~liter/day
saliva functions?
1) wet and lubricate oral mucosa
2) protect the oral mucosa and teeth
3) antimicrobial activity
4) initiate digestion of carbohydrates
5) hydrolysis of dietary lipids in newborns (lingual lipase)
what are parenchya
parenchyma: secretory units and ducts
what are stroma
connective tissue supporting the parenchyma and containg cells, blood vessels, nerves
what kind of glands are salivary glands?
compound tubuloacinar / compound acinar glands
organization of saliva glands
capsule
CT septa
lobes
lobules
secretory units
ducts
tubular gland structure?
gland has 1 duct opening into 1 very elongated secretory unit that is tubular shape
can be single simple or branched ducts w/ compound gland
acinar/alveolar gland structure
spherical gland
simple: 1 duct-1 gland
compound: multiple ducts/multiple glands
tubuloacinar gland structure
combo of tubular and acinar gland
salivary gland can be tubular, acinar, or tubuloacinar
acini
secretory units (end pieces) of exocrine glands, whether rounded or tubular on sections
how are acini classified
according to the nature of secretions they produce
types of acini?
serous, mucous
what are these
serous- watery secretion rich in enzymes & mucous- viscous secretion rich in glycoproteins - secretions from acini
types of acini of salivary glands?
1) serous acini
2) mucous acini
3) mixed acini, composed of mucous cells & serous cells, the latter making serous demilunes
what is this, what is arrow pointing to
mixed acini (in submandibular gland)
arrow > serous demilnue, consists of serous cells forming a semilunar cap at terminal portion of mucous acinus
what is this
myoepithelial cells located btwn basal plasma membranes of acinar cells & basement membranes
make up of myoepithelial cells?
actin, cytokeratin
have contractility
what is this
salivary gland
showing arrangement of acini and intralobular ducts
cell type of duct cells?
simple columnar epithelium w/ basal striations
what marks mitochondrial enzymes?
succinic dehydrogenase
striated duct
marked by SDH in mitochondria
cell type lining intercalated / striated intralobular duct cells?
intercalated: simple cuboidal epithelium
striated: simple columnar epithelium
cell types of interlobular, lobar, and main excretory ducts?
interlobular: psuedostratified columnar
lobar: stratified columnar
main: stratified squamous
interlobar ducts between lobes
what type of gland is parotid?
pure serous gland
ONLY serous acini; intercalated ducts; conspicuous striated ducts
what is this
parotid gland
pure serous gland
what is this
submandibular gland
mixed gland; serous acini > mucous acini
mixed acini w/ serous demilunes
intercalated ducts
conspicuous straited ducts
what is this
sublingual gland
mixed gland
mucous acini > serous acini
mixed acini w/ serous demilunes
intralobular ducts are poorly developed
rank salivary glands re: intercalated duct size
1) parotid
2) submandibular
3) sublingual - rare or absent intercalated ducts
rank salivary glands re: straited duct size
well-developed: parotid, submandibular
poorly developed: sublingual
how much of saliva does each salivary gland contribute? what is nature of secretion?
parotid: 30%, watery, rich in enzymes
sublingual: 5%, thick, mucous
submandibular: 60%, mixture of enzyme & mucous secretion of intermediate consistency
describe functional unit of salivary gland
describe saliva
hypotonic, alkaline solution in oral cavity
other functions of saliva?
lubrication
protection
antimicrobial activity
function of secretory IgA?
component of saliva with antibacterial and antiviral actions
other functions of saliva
1) lubrication, protection, antimicrobial activity
2) antibacterial, antiviral via Secretory IgA
3) digestion of carbs via starch
4) growth factors- epidermal growth factor, nerve growth factor
5) biological active proteins (cystatins, histatins, proline-rich proteins)
6) calcium for phosphate for remineralization of teeth
pellicles?
proline-rich protective coat saliva forms on teeth
prevents adherence of bacteria, yeast
what do parasympathetic/sympathetic control of saliva contribute to?
parasympathetic: watery, electroyte rich saliva; high volume
sympathetic: viscous, mucin and protein rich saliva; low volume
how do exocrine secretions leave pancreas?
main pancreatic duct joins bile duct to open into duodenum
duct carrie secretion of exocrine pancreas into duodenum
what kind of gland is pancreas?
compound acinar gland - has CT septa, lobes, lobules
serous pancreatic acini
contain centroacinar cells in lumen
centroacinar cells from beginning portion of intercalated duct of exocrine pancreas
what and where is this? type of release involved?
zymogen granules of pancreatic acinar cells
digestive enzymes within are released by merocrine mechanism
what/when does pancreas secrete?
pancreas secretes a fluid containing digestive enzymes & bicarbonate ions & water in response to acid chyme in duodenum & jejunum
what do pancreatic acinar cells secrete?
an enzyme-rich fluid
stimulated by cholescystokinin (CCK)
contains many digestive enzymes
what do pancreatic duct cells secrete? stimulated by what?
a fluid rich in bicarbonate ions & water
secretion is stimulated by secretin
autonomic nerves are secondarily important to secretion
what is same/different about exocrine pancreas and parotid gland?
both= compound acinar gland, contains only serous secretory acini
HOWEVER, pancreas distinguishable histologically from parotid by:
1) presence of centroacinar cells
2) absence of straited ducts
3) absence of myoepithelial cells
