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Digestive glands. General outline. small digestive glands. distributed in the wall of digestive tract esophageal glands, gastric glands and intestine glands. large digestive glands. outside the wall of digestive tract salivary glands, liver and pancreas. Large salivary glands.

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general outline
General outline
  • small digestive glands
  • distributed in the wall of digestive tract
  • esophageal glands, gastric glands and
  • intestine glands
  • large digestive glands
  • outside the wall of digestive tract
  • salivary glands, liver and pancreas
large salivary glands
Large salivary glands
  • Include parotid, submandibular and

sublingual glands

  • are compound tubuloacinar glands
  • are composed of acini and ducts
acinus
Acinus :
  • acinar epithelium: simple

cuboidal or pyramidal cells

  • myoepithelial cell
  • basal membrane

Structure:

Serous acini

Mucous acini

Mixedacini

Be divided into

serous acini
Serous acini
  • cytoplasma are deep stained
  • nucleus are spherical in shape and near

the base

  • secretion is thin, contains salivary amylase

and a little mucus

mucous acini
Mucous acini
  • cytoplasma are light-blue stained
  • nucleus are flattened ovoid shaped and

close to the base

  • secretion is thick; contains mucoprotein
mixed acini
Mixedacini
  • consist of above two kinds of cells
  • demilunes: several serous cells are

attached eccentrically to the mucous acini

ducts
Ducts:
  • Intercalated ducts

diameter: thinnest

wall: simple low cuboidal epithelium

slide12

Striated duct (secretory duct)

  • wall: simple columnar epithelium; the nucleus

is near the cell apex; cytoplasm is

acidpphilic; has basal striations

  • EM: the basal striations created by

membrane infolding and mitochondia

  • reabsorbing sodium and excreting potassium;

transport water and ions

slide14

Interlobular duct

Wall: pseudostratified epithelium

  • Main duct

Near its orifice become stratified

squamous epithelium

parotid gland
Parotid gland
  • pure serous gland
  • longer intercalated duct
  • secrete 25% of saliva, more salivary

amylase, less mucus

submandibular gland
Submandibular gland
  • mixed gland. Serous acini are more than

mixed or mucous acini

  • short intercalated duct, longer striated duct
  • secrete 70% of saliva, less salivary amylase,

more mucus

sublingual gland
Sublingual gland
  • mixed gland, mucous and mixed acini

predominant, more demilune

  • without intercalated duct, obscure striated

duct

  • secrete 5% of saliva, most mucus
pancreas
Pancreas

Exocrine portion:

  • the features of the acini
  • a single layer of pyramidal serous cells

surrounded by basal lamina, without

myoepithelial cells

  • centro-acinar cells: the epithelial cells of

intercalated duct penetrating into the

lumen of the acinus

slide22

the feature of ducts

  • the intercalated duct is long and has branches
  • no striated duct
  • main duct: lined by simple columnar

epithelium in which a few goblet cells

and endocrine cells can be seen

slide23

The functions of exocrine portion

Secret abundant trypsinogen,

chymotrypsinogen, amylase, lipase,

sodium bicarbonate and trypsin inhibitor

endocrine portion pancreatic islet
Endocrine portion (pancreatic islet):
  • rounded clusters of cells embedded within

exocrine pancreatic tissue

  • are divided into three kinds of cells: A, B,

and D cells

  • fenestrated capillaries are among the

cells

slide29

Endocrine portion

PP cells: pancreatic polypeptide

G cells: gastrin

Other cells

slide30

A cells

B cells

D cells

liver
Liver

Hepatic plates

Sinusoid

Central vein

Liver lobule

Interlobular arteries

Interlobular veins

Interlobular bile ducts

Portal area

slide33

Functions of liver:

  • bile secretion
  • synthesize: protein, glycogen, cholesterin
  • detoxification and inactivation
  • defence
  • hemopoiesis
slide34

Human liver

Pork liver

liver lobule
Liver lobule:
  • hepatic plates: are composed of a single

layer of hepatocytes arranged in radial

  • sinusoid: situated between the hepatic

plates, forming a complex network

  • central vein: occupies the centre of the

liver lobule

hepatocytes
Hepatocytes
  • polyhedral in shape, eosinophilic cytoplasm,

one or two large rounded nuclei with one or 2

typical nucleoli

  • EM: Mi, RER, SER, Golgi apparatus,

lysosomes, microbodies, inclusions

slide41

Mitochondria

provide the energy for the hepatocytes

  • Rough endoplasmic reticulum

synthesize some plasma proteins

  • Golgi apparatus

participate in the formation of bile and lipoprotein

slide42

Smooth endoplasmic reticulum

  • synthesize bile, triglyceride and LDL
  • metabolism of the lipid, hormones and

cholerythrin

  • inactivate steroid hormone
  • biotransformation of some materials
  • detoxification of noxious substances
slide43

Lysosomes

  • actively participate the metabolism of

hepatocyte and renewal of organelles

  • play a role in metabolism and transport of

cholerythrin

  • storage of iron
slide44

Microbodies

detoxification: catalase and peroxidase;

reduce the hydrogen peroxide into H2O

  • Inclusions

include glycogen, lipid droplets, pigment etc;

These contents vary according to physiologic state of human body

bile canaliculi
Bile canaliculi
  • between two adjacent hepatocytes
  • the membrane of hepatocyte projects to

the lumen, forming many microvilli

  • the cell membranes near the bile canaliculi

are firmly bound by junctional complexes

liver sinusoid
Liver sinusoid
  • spaces between the hepatic plates
  • irregular in shape
  • composed of only one discontinuous layer of

fenestrated endothelial cells, no diaphragm,

no basement membrane

  • Kupffer cells are located within the sinusoid

cavities

space of disse
Space of Disse
  • separates the endothelium from the

hepatocytes

  • contains some reticular fibers and fat-storing

cells

portal space
Portal space:
  • the connective tissue separating the lobules
  • including

Interlobular arteries

Interlobular veins

Interlobular bile ducts

blood circulation
Blood circulation:

portal V.

interlobular V.

(functional vessel)

sinusoids

central V.

hepatic A.

interlobular A.

sublobular V.

(nutrient vessel)

hepatic V.

slide55

Blood vessels of liver

(prepared Chinese ink injection through portal vein)

discharge way of bile
Discharge way of bile:

Bile canaliculi

Hering’s canals

Interlobular bile ducts

Gallbladder

Hepatic duct

Common bile duct

Cystic duct

duodenum

gallbladder
Gallbladder

Simple columnar Epi. , no Goblet cells

Laminar propria: C.T.

  • mucosa
  • muscle layer: composed of an inner circular,

an outer longitudinal layers of smooth muscle

  • adventitia: most are fibrosa, some are serosa