accessory glands/ histology Flashcards
what is a gland
an organised cluster of secretory units
functions of digestive glands
lubrication
protection
digestion and absorption
portions of salivary gland
secretory and duct regions
two types of cells (acini)
serous and mucous
held together by myoepithelial cells
duct system in salivary gland
intercalated -> striated -> interlobular -> interlobar -> principle
three types of salivary gland
parotid
submandibular
sublingual
parotid gland produces
water (serous) solution, about 25% total
submandibular gland produces
both serous and mucous, 70% total
sublingual gland produces
mucous secretion, 5% total
main enzyme in saliva
alpha amylase
main components of saliva
proteins, glycoproteins, ions, water IgA
arrangement of cells in saliva
secreter portions arranged in acini with the 3 cell types
type of epithelium in salivary gland
stratified squamous
autonomic regulation of salivary glands
parasympathetic most important
ach stimulates primary secretion, get large amounts of watery saliva
pancreas exocrine structure
compound tubulocacinar gland
pancreas exocrine function
produces digestive pro enzymes
apex of acinar cells facing lumen is filled with pro enzyme secretory granules
pancreatic duct opening into duodenum
at the papilla of vater
cell type in liver
hepatocytes
where do blood cells enter and leave the liver
porta hepatis
also where bile leaves
triad structure in liver
portal areas have branches of the hepatic artery, tributaries of portal vein, interlobular bile ducts vein = biggest artery = smallest bile duct has more symmetrical wall sinusoids between hepatocytes
resident macrophages in liver
kupffer cells phagocytic breakdown of RBC liver response to infection, toxins, ischaemia mononuclear phagocytes
apical and basolateral borders of hepatocytes
basolateral (sinusoidal) = absorbs blood-borne substances and secretes plasma proteins
apical (canalicular) = borders the bile canaliculus, sealed at the sides by occluding unctions
function of hepatic stellate cells
protean, multifunctional and enigmatic
versatile mesenchymal cells
become activated in response to liver injury and repair
liver major functions
bile production
detoxification
major role in metabolism - carbohydrate, amino acid and lipid
breakdown of insulin and other hormones
what is the space of disse
space between a hepatocyte and sinusoid
contains the blood plasma
where microvilli of hepatocytes extend into
allowing proteins and other components to be absorbed
bile canaliculi
collect bile secreted by hepatocytes
drain into increasing size of bile ducts
direction of bile movement opposite to blood movement
blood flow through lobule
passes from triad (hepatic artery and portal vein) into the central vein (hepatic vein into IVC)
gall bladder function
stores, concentrates and releases bile
pouch around gallbladder neck
Hartmans pouch
wall of gall bladder
epithelium
lamina propria
smooth muscle
adventitia
gall bladder histology features
- folded mucosa with single layer of columnar epithelia and microvilli
- submucosa has lymphatics
- serous is a thick layer that covers the outer surface
- no muscularis layer
- muscle fibres not in distinct layers
gallstones
formed in gallbladder out of precipitated bile components
painful when they obstruct the bile duct
formed from cholesterol, bile salts and bilirubin
spleen components
white pulp and red pulp
thin fibrous capsule
function of spleen
phagocytosis and immune response
white pulp contains
lymphoid tissue, B/T lymphocytes
red pulp contains
macrophages
secretory cell function in salivary gland
serous = secrete proteins and polysaccharides mucous = secrete mucous
duct function in salivary gland
highly branched intercalated ducts which can modify and delivery acinar secretions to terminal ducts -> oral cavity
myoepithelial basket cells function in salivary glands
several long processes that envelop the acini
sinusoid function in liver
open pore capillaries permeable to small molecule,s allowing their passage between hepatocytes and blood stream
portal triad function
contains branches of hepatic artery, portal vein and bile duct
provides oxygen, nutrients to hepatocytes and bile duct carries products away too gall bladder
pancreas acini functions
exocrine glands which produce digestive pro-enzymes eg. trypsinogen and chymotrypsinogen
pancreas duct functions
deliver pro enzymes to duodenum
function of centroacinar cells in pancreas
occupy lumen of acinus and secrete buffer solution providing alkaline pH for enzyme activity
secretory units of salivary glands
acini
can be serous, mucous or mixed
secretory glands drain into (saliva)
intercalated ducts
lined by simple cuboidal
surround by myoepithelail cells
intercalated ducts drain into
striated ducts
where secondary modifications occur
what do serous acini have in the cytoplasm
zymogen granules
