Digestive Digestive glandgland

---small ---small digestive glands: digestive glands: gastric gland, intestinal gastric gland, intestinal gland…gland…

---large digestive glands: ---large digestive glands: salivary glands, pancreas, salivary glands, pancreas, liverliver

General structure of Salivary General structure of Salivary glandsglands

a.a. serous acinus:serous acinus: ---- structure: ---- structure: Serous secretory cellsSerous secretory cells----secretion: ----secretion: Watery fluid containingWatery fluid containingsalivary amylasesalivary amylase

acinusacinus

b. b. mucous acinusmucous acinus: : ----structure:----structure: mucous secretory cellsmucous secretory cells----secretion: ----secretion: viscous fluid containing viscous fluid containing mucus(glycoprotein)mucus(glycoprotein)

the above two types of secretory cellsthe above two types of secretory cells

serous demiluneserous demilune

c. c. Mixed acini and demiluneMixed acini and demilune

Myoepithelial cellsMyoepithelial cells

function:

intercalated ductintercalated duct simple squamous epi.simple squamous epi. simple cuboidal epi.simple cuboidal epi.

striated duct (secretory duct)striated duct (secretory duct) simple columnar epi. tall cell, acidophilic, round N, located simple columnar epi. tall cell, acidophilic, round N, located

at apical partat apical part longitudinal striation: longitudinal striation:

The characteristics of 3 pairs of salivary glandsThe characteristics of 3 pairs of salivary glands

Parotid glandParotid gland Submandibular glanSubmandibular glandd

Sublingual Sublingual glandgland

AciniAcini

DuctsDucts

SecretionSecretion

Pure serous glandPure serous gland

Long I.D.Long I.D.

short S.D.short S.D.

More salivary More salivary amylase,amylase,

less mucusless mucus

Mixed gland,Mixed gland,

More serous aciniMore serous acini

Short I.D.,Short I.D.,

Long S.D.Long S.D.

Less salivary amylaLess salivary amylase,se,

more mucusmore mucus

Mixed gland, Mixed gland, more mixed anmore mixed and mucous acinid mucous acini

Without I.D. sWithout I.D. short S.D.hort S.D.

Most mucusMost mucus

General structure of General structure of PancreasPancreas

/exocrine portion/exocrine portion

/endocrine portion/endocrine portion(pancreas islets ,secret hormones)(pancreas islets ,secret hormones)

function:function:

exocrine portionexocrine portion

----Consists of serous cells ----Without myoepithelial cells ----With several centroacinar cells in acinus cavity--------Long I.D. ,no S.D.

---small spherical clusters ---small spherical clusters composed of endocrine cells of composed of endocrine cells of pancreaspancreas

endocrine portionendocrine portion( pancreas islets)( pancreas islets)

---EM: ---EM: A cellsA cells 20% 20% peripheral-distributedperipheral-distributed function: secret glucogonfunction: secret glucogon      B cellB cell 70%70% centrally-distributedcentrally-distributed function: secret insulinfunction: secret insulin

D cellsD cells 5%5% distributed between A, B cells,have gap junction widistributed between A, B cells,have gap junction wi

th A,B cellsth A,B cells function:function:

PP cellsPP cells

/hepatic lobule/hepatic lobule/portal area/portal area

liver

Hepatic platesHepatic plates

a single layer of hepatocytes arranged radially around the CV.

Hepatic cords

Central veinCentral vein

Structure of classic hepatic lobule

hepatocytehepatocyte

LM:LM: large ,20-30 um large ,20-30 um polygonal, polygonal, eosinophilic (stains poorly because stored glycogen and faeosinophilic (stains poorly because stored glycogen and fa

t are dissolved during preparation)t are dissolved during preparation) N: large, pale, round, centrally- located with obvious nucN: large, pale, round, centrally- located with obvious nuc

eulus,about 25% are binucleateeulus,about 25% are binucleate

Mitochondria:Mitochondria: RER: RER: SER: SER: Lysosome: Lysosome: Golgi apparatusGolgi apparatus MicrobodiesMicrobodies

EM:EM:Well-developed organellsWell-developed organells

InclusionsInclusions

----space between the hepatic plates

hepatic sinusoid

hepatic macrophage (Kupffer cell)

macrophage in hepatic sinusoid

Large granular lymphocyte

Perisinusoidal space Perisinusoidal space (space of Disse)(space of Disse)

**fat-storing cellfat-storing cell (Ito cell) (Ito cell)

----irregular, with processes----irregular, with processes----function: store the vitamin A, synthesis the ----function: store the vitamin A, synthesis the

collagencollagen

----cell membrane of adjacent hepatocyte----cell membrane of adjacent hepatocytes depress to form a tubular system betws depress to form a tubular system between hepatocyteseen hepatocytes

bile canaliculusbile canaliculus

---contacting with adjacent hepatocyte---contacting with adjacent hepatocyte ---facing the sinusoids through the Disse space ---facing the sinusoids through the Disse space ---forming a bile canaliculus---forming a bile canaliculus

* The three kinds of functional surfaces of hepatocytes* The three kinds of functional surfaces of hepatocytes

portal areaportal area

interlobular artery:interlobular artery:

  interlobular veininterlobular vein: :

interlobular bile ductinterlobular bile duct: :