Chapter 14
Digestive gland
---small gland,fundis gland,small
intestinal gland
---large gland,salivary gland,
pancreas,liver
1,Salivary gland
1) General structure of exocrine gland
---Capsule,CT,which separate the
parenchyma into lobules
---lobule:
① acinus:
a,serous acinus:
structure:
pyramidal or cuboidal
round basally-located N
apical,zymogen granule-acidophilic
basal,basophilic-RER,ribosome
function,secret salivary amylase
b,mucous acinus:
structure:
pale-stained,slight-blue,flattened N against
the basal membrane
mucinogen granule
Golgi,RER,mitochondria
c,mixed acinus,several serous cell attached to
mucous acinus – serous demilune
② duct:
a,intercalated duct:
simple squamous epi.
simple cuboidal epi.
connect with acinus
b,striated duct
(secretory duct),intralobule
simple columnar epi.,
tall cell,acidophilic
round N,located at apical part
longitudinal striation,plasma membrane
infolding
c,interlobular duct and major duct, simple
columnar epi,or pseudostratified ciliated
columnar epi.
2) structural feature of each salivary gland
a,parotid gland:
-serous
-long intercalated duct,short striated duct
b,submandibular gland:
-mixed( mainly serous,less mucous and mixed)
-short intercalated duct,long striated duct
c,sublingual gland:
-mixed(mainly mucous,more serous and
mixed)
-more demilunes,no intercalated duct,
under-developed striated duct
* granular convoluted tubule,GCT:
---a segment convoluted duct between intercalated
duct and striated duct in submandibular gland
---epithelial cell:
pyramidal in shaped,with large N
apical cytoplasma,eosinophilic granules
granules contain:
i,growth factors-NGF,EGF,MGF,EGSF,EGF
ii,homeostasis factors,renin,Kallikrein,CSF,ACF
iii,digestive enzymes,amylase,ribonuclease,acid
phosphatase
iv,intracellular regulating factor
2,Pancreas
---capsule,CT,septa
---parenchyma:
/exocrine pancreas
/endocrine pancreas
1) exocrine pancreas
---acinus,serous
*centroacinar cell,small,pale cell with round or ovoid
N,derived from epithelial cell of intercalated duct
---duct,long intercalated duct
---function,secret pancreatic liquid
1-2L/D,PH 7.8-8.4
Digestive enzymes,trypsinogen,chymotrypsinogen,
amylase and lipase
2) endocrine pancreas( pancreas islet)
---170.000-200.000,constitute about 1%
of total pancreas volume
---75-500 um
---HE,cells arranged into cord with CT
rich in fenestrated cap.
---EM:
a,A cell:
20%,Large polygonal in shaped,peripheral-
distributed
EM,secretory G,large,190-310 nm,round
with dense core
function,secret glucogon - 29 amino acid
residues protein ↓
glycogen→ glucose
b,B cell:
75%,small,centrally-distributed
EM,secretory G,different diameter,225-375
nm with one or several dense core
function,secret insulin - 51 amino-acid
residues
c,D cell:
5%,ovoid,fusiform,peripheral-distributed,
between A,B cells
EM:
-gap junction with A,B cell
-secretory G,large,190-370nm,low-
density core
function,secrete somatostatin to inhibit the
secreting of A,B,PP cell
d,PP cell:
EM,secrete granule,small,110-170 nm
function,secrete pancreatic polypeptide to
inhibit the secreting of pancreatic liquid,
movement of viscera and contraction of gall
bladder
e,D1 cell:
2-5%,peripheral,irregular
EM,small,140-190 nm,
function,secrete VIP(vasoactive intestinal
peptide)
f,C cell,undifferentiated cell
3,Liver
---largest,2% of body weight
---capsule,DCT,insert into parenchyma to
separate the parenchyma into hepatic lobule
---hepatic lobule
---portal area
1) hepatic lobule,basic structural
unit
---500.000-1.000.000
---2 mm long,1 mm in across D
---polygonal prism( irregular)
---structure:
central vein
hepatic plate,radiating
arranged
hepatic sinusoid
① Central vein:
small vein,endothelium + CT
45 um
receive the blood from sinusoids
② Hepatic plates
---formed by
single layer of hepatocytes
a,hepatocyte:
LM:
polygonal,20-30 um
eosinophilic
N,-large,pale,round,centrally- located
-1/4 binucleate
EM:
mitochondria,1000-2000,20% total volume
RER,involve in the synthesis of albumin,
fibrinogen,clotting factor,lipoprotein and
complement protein
SER,contain enzymes- oxidoreductase (oxidase,
reductase),hydrolase,transterase,synthetase,
involve in the formation of bile and the
metabolism of adipose,glucose and hormones
Golgi apparatus,involve in
-formation of bile
-process,condense and storage of proteins
-formation of lysosome
Lysosome,involve in phagocytosis activity
and metabolism of bilirubin
microbody:
-round,0.2-1.0 um
-contain catalase and peroxidase
inclusions,glycogen,lipid droplet,pigment
b,bile canaliculus:
---cell membrane of adjacent hepatocytes
depress to form a tubular system
between hepatocytes
---structure:
silver preparation,dark-brown colored
network
0.5-1um
Microvilli
tight junction,desmosome
③ Hepatic sinusoid
---space between hepatic plates
---structure:
LM:
9-12 um
endothelial cell,fenestrated,
gap,plasmalemmal vesicles
RF
cavity:
-liver macrophage(Kupffer cell)
-large granular lymphocyte,NK
cell
EM:
Perisinusoidal space,Disse space -
narrow space between endothelial cell
and hepatocytes
0.4 um width
blood plasma
microvilli
RF
fat-storing cell:
*fat-storing cell:
-irregular,with processes
-EM,large lipid droplets,RER,mito,
Golgi
-function,storage of vitamin A(E,K),
synthesis of collagen
* The three kinds of different
surfaces of hepatocytes
---face adjacent cell each
other,55%
---face the sinusoids,35%
---form bile canaliculus,10%
2) portal area
---areas(triangle-shaped or irregular-shaped)
where adjacent hepatic lobules meet
---contains CT and several ducts
a,interlobular arteries:
branches of hepatic A
small A,endothelium + 3-4 layers of SM
b,interlobular vein:
branches of portal vein
small vein,endothelium + less CT and single
SM
c,interlobular bile duct:
simple cuboidal or low columnar epi.
3) Blood circulation of liver
hepatic A →interlobular A →terminal hepatic arteriole
portal V→interlobular V→terminal portal venule
→ hepatic sinusoid →central vein→sublobular V
→hepatic V→inferior vena cava
4) Passage of bile
｛
Digestive gland
---small gland,fundis gland,small
intestinal gland
---large gland,salivary gland,
pancreas,liver
1,Salivary gland
1) General structure of exocrine gland
---Capsule,CT,which separate the
parenchyma into lobules
---lobule:
① acinus:
a,serous acinus:
structure:
pyramidal or cuboidal
round basally-located N
apical,zymogen granule-acidophilic
basal,basophilic-RER,ribosome
function,secret salivary amylase
b,mucous acinus:
structure:
pale-stained,slight-blue,flattened N against
the basal membrane
mucinogen granule
Golgi,RER,mitochondria
c,mixed acinus,several serous cell attached to
mucous acinus – serous demilune
② duct:
a,intercalated duct:
simple squamous epi.
simple cuboidal epi.
connect with acinus
b,striated duct
(secretory duct),intralobule
simple columnar epi.,
tall cell,acidophilic
round N,located at apical part
longitudinal striation,plasma membrane
infolding
c,interlobular duct and major duct, simple
columnar epi,or pseudostratified ciliated
columnar epi.
2) structural feature of each salivary gland
a,parotid gland:
-serous
-long intercalated duct,short striated duct
b,submandibular gland:
-mixed( mainly serous,less mucous and mixed)
-short intercalated duct,long striated duct
c,sublingual gland:
-mixed(mainly mucous,more serous and
mixed)
-more demilunes,no intercalated duct,
under-developed striated duct
* granular convoluted tubule,GCT:
---a segment convoluted duct between intercalated
duct and striated duct in submandibular gland
---epithelial cell:
pyramidal in shaped,with large N
apical cytoplasma,eosinophilic granules
granules contain:
i,growth factors-NGF,EGF,MGF,EGSF,EGF
ii,homeostasis factors,renin,Kallikrein,CSF,ACF
iii,digestive enzymes,amylase,ribonuclease,acid
phosphatase
iv,intracellular regulating factor
2,Pancreas
---capsule,CT,septa
---parenchyma:
/exocrine pancreas
/endocrine pancreas
1) exocrine pancreas
---acinus,serous
*centroacinar cell,small,pale cell with round or ovoid
N,derived from epithelial cell of intercalated duct
---duct,long intercalated duct
---function,secret pancreatic liquid
1-2L/D,PH 7.8-8.4
Digestive enzymes,trypsinogen,chymotrypsinogen,
amylase and lipase
2) endocrine pancreas( pancreas islet)
---170.000-200.000,constitute about 1%
of total pancreas volume
---75-500 um
---HE,cells arranged into cord with CT
rich in fenestrated cap.
---EM:
a,A cell:
20%,Large polygonal in shaped,peripheral-
distributed
EM,secretory G,large,190-310 nm,round
with dense core
function,secret glucogon - 29 amino acid
residues protein ↓
glycogen→ glucose
b,B cell:
75%,small,centrally-distributed
EM,secretory G,different diameter,225-375
nm with one or several dense core
function,secret insulin - 51 amino-acid
residues
c,D cell:
5%,ovoid,fusiform,peripheral-distributed,
between A,B cells
EM:
-gap junction with A,B cell
-secretory G,large,190-370nm,low-
density core
function,secrete somatostatin to inhibit the
secreting of A,B,PP cell
d,PP cell:
EM,secrete granule,small,110-170 nm
function,secrete pancreatic polypeptide to
inhibit the secreting of pancreatic liquid,
movement of viscera and contraction of gall
bladder
e,D1 cell:
2-5%,peripheral,irregular
EM,small,140-190 nm,
function,secrete VIP(vasoactive intestinal
peptide)
f,C cell,undifferentiated cell
3,Liver
---largest,2% of body weight
---capsule,DCT,insert into parenchyma to
separate the parenchyma into hepatic lobule
---hepatic lobule
---portal area
1) hepatic lobule,basic structural
unit
---500.000-1.000.000
---2 mm long,1 mm in across D
---polygonal prism( irregular)
---structure:
central vein
hepatic plate,radiating
arranged
hepatic sinusoid
① Central vein:
small vein,endothelium + CT
45 um
receive the blood from sinusoids
② Hepatic plates
---formed by
single layer of hepatocytes
a,hepatocyte:
LM:
polygonal,20-30 um
eosinophilic
N,-large,pale,round,centrally- located
-1/4 binucleate
EM:
mitochondria,1000-2000,20% total volume
RER,involve in the synthesis of albumin,
fibrinogen,clotting factor,lipoprotein and
complement protein
SER,contain enzymes- oxidoreductase (oxidase,
reductase),hydrolase,transterase,synthetase,
involve in the formation of bile and the
metabolism of adipose,glucose and hormones
Golgi apparatus,involve in
-formation of bile
-process,condense and storage of proteins
-formation of lysosome
Lysosome,involve in phagocytosis activity
and metabolism of bilirubin
microbody:
-round,0.2-1.0 um
-contain catalase and peroxidase
inclusions,glycogen,lipid droplet,pigment
b,bile canaliculus:
---cell membrane of adjacent hepatocytes
depress to form a tubular system
between hepatocytes
---structure:
silver preparation,dark-brown colored
network
0.5-1um
Microvilli
tight junction,desmosome
③ Hepatic sinusoid
---space between hepatic plates
---structure:
LM:
9-12 um
endothelial cell,fenestrated,
gap,plasmalemmal vesicles
RF
cavity:
-liver macrophage(Kupffer cell)
-large granular lymphocyte,NK
cell
EM:
Perisinusoidal space,Disse space -
narrow space between endothelial cell
and hepatocytes
0.4 um width
blood plasma
microvilli
RF
fat-storing cell:
*fat-storing cell:
-irregular,with processes
-EM,large lipid droplets,RER,mito,
Golgi
-function,storage of vitamin A(E,K),
synthesis of collagen
* The three kinds of different
surfaces of hepatocytes
---face adjacent cell each
other,55%
---face the sinusoids,35%
---form bile canaliculus,10%
2) portal area
---areas(triangle-shaped or irregular-shaped)
where adjacent hepatic lobules meet
---contains CT and several ducts
a,interlobular arteries:
branches of hepatic A
small A,endothelium + 3-4 layers of SM
b,interlobular vein:
branches of portal vein
small vein,endothelium + less CT and single
SM
c,interlobular bile duct:
simple cuboidal or low columnar epi.
3) Blood circulation of liver
hepatic A →interlobular A →terminal hepatic arteriole
portal V→interlobular V→terminal portal venule
→ hepatic sinusoid →central vein→sublobular V
→hepatic V→inferior vena cava
4) Passage of bile
｛
