12 digestive glands
TRANSCRIPT
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The Digestive System
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Exocrine gland---with ductExocrine gland---with duct
Constituents of multicellular gland:Constituents of multicellular gland:
secretory portion:secretory portion: tubular,acinar or tubuloacinartubular,acinar or tubuloacinar
gland duct:gland duct: passage of secretionspassage of secretions
Endocrine gland---without duct
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Exocrine glandExocrine gland
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Salivary glandSalivary glandAcinus: mucous acinus, serous acinus ,mixed acinus
Duct: intercalated duct,striated duct,interlobular duct and
common duct
Serous acinus Mucous acinus
Cell type
Cytoplasm
ucleus
Secretions
Serous cell
Deep stained
Spherical,near the base
Protein
Mucous cell
Light-blue stained
spindle,near the base
Mucoprotein (mucus)
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Salivary glandSalivary gland
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Serous aciniSerous acini
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Mucous aciniMucous acini
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Mixed acini and semiluneMixed acini and semilune
Semilune: several serous
cells arranged like half-moon
in the mixed acinus
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Salivary glandsSalivary glands
1. components: parotid gland,submandibular1. components: parotid gland,submandibular
gland and sublingualgland and sublingual
gland,etc.gland,etc.
2. function: secreting saliva.2. function: secreting saliva.
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The characteristics of 3 pairs of salivary glandsThe characteristics of 3 pairs of salivary glands
Parotid gland Submandibular gland Sublingual gland
Acini
Ducts
Secretion
Pure serous gland
Long I.D.
25% saliva
More salivaryamylase,
less mucus
Mixed gland,
More serous acini
Short I.D.,
Long S.D.
70% saliva
Less salivaryamylase,
more mucus
Mixedgland,moremixed and
mucous acini
Without I.D.
5% saliva
Most mucus
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Parotid gland---pure serous glandParotid gland---pure serous gland
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Submandibular gland---mixed glandSubmandibular gland---mixed gland
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Sublingual gland---mixed glandSublingual gland---mixed gland
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PancreasPancreas
Parenchyma: exocrine portion: pancreatic secretions involved in
food-digestion.
endocrine portion(pancreas islet): secreting hormones
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1. Exocrine portion1. Exocrine portion
acini
ducts
Consists of serous cells surrounded
by basal lamina
Without myoepithelial cells,With several centro-acinar cells
in acinus cavity.
Long I.D. ,no S.D.
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Exocrine portion of pancreasExocrine portion of pancreas
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Exocrine portion of pancreasExocrine portion of pancreas
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2. Endocrine portion2. Endocrine portion
(pancreas islet)(pancreas islet)
A cell B cell D cell PP cell
Rate(%)
Distribution
Secretion
20%
Periphery
Glucagon--Increase bloodglucose levelsblood glucoselevels
70%
Center
Insulin--Decreaseblood glucoselevels
5% 5%
Somatostatin Pancreas
Inhibit the secretion polypeptide
of other cells
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Diabetes:Diabetes: absence or inadequate amounts ofabsence or inadequate amounts of
insulin.insulin.
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The largest digestive gland.The C.T.sends the septa into the parenchyma,
separating the hepatic lobules.
The portal area is present at the corner of the lobules.
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Classic hepatic lobuleClassic hepatic lobule
It is a structural unit of liver.Components
Hepatic plates: a single layer of hepatocytes arranged in radial.
Sinusoids:between hepatic plates and anastomosewith each other.
Central vein: occupies the centre of the liver lobule.
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hepatocytehepatocyte
3 functional surfaces:sinusoidal..,canalicular..,intercellular..
LM:
Profile:large,polyhedral in shape.
Cytoplasm:rich in Mitochondria,
Golgi complex, SER,RER,
lipid droplets, glycogen,etc.
Nucleus: large,central,lightly stained,
with obvious nuceulus.
EM: numerous microvilli protruding
into sinusoids and bile canaliculi.
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Function of hepatocyteFunction of hepatocyte
1.Bile secretion1.Bile secretion
2.Synthesis and storage2.Synthesis and storage
3.Detoxification and inactivation3.Detoxification and inactivation
4.Defence :related to Kuffer cell4.Defence :related to Kuffer cell
5.Hemopoiesis5.Hemopoiesis
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Bile canaliculusBile canaliculus
It is a small canal formed by opposed groovesIt is a small canal formed by opposed grooves
In the surface of adjacent hepatocytes.In the surface of adjacent hepatocytes.
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Bile canaliculiBile canaliculi
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Space of DisseSpace of Disse
ce between hepatocytesendothelium.
rovilli of hepatocytesrude into it, whichance the exchagesaterials.
ing fat cells :in spaceisse.responsible forstorage of Vit.A anduction of fibers.
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Portal areaPortal area portal canalsportal canals
portal triad:portal triad:
Interlobular arteries
Interlobular veins
Interlobular bile ducts
Hepatic artery
Portal vein
Common bile duct
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Hepatic circulationHepatic circulation
Common bile duct
Portal vein
Hepatic artery
Hepatic vein
Interlobular bileducts
Interlobular vein
Interlobular artery
vein
Bile canaliculi
sinusoids
Central vein
Hepatic hilum Hepatic lobulePortal area
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Key pointsKey points
1. The structure and function of pancreas.1. The structure and function of pancreas.
(exocrine portion and endocrine portion),the(exocrine portion and endocrine portion),the
cellular components of pancreas islet andcellular components of pancreas islet andtheir function.their function.
2.The definition of hepatic lobule and portal2.The definition of hepatic lobule and portalarea.sinusoid ,space of Disse,Kuffer cell;area.sinusoid ,space of Disse,Kuffer cell;
3.The formation of bile canaliculi.3.The formation of bile canaliculi.