The extrinsic glands of the digestive system i

nclude the major salivary glands, the pancreas, a

nd the liver, all of which are located outside the

wall of the digestive tract.

The major salivary glands consist of three pai

r of glands: the parotid, submandibular glands an

d sublingual glands.

Fig. 1 Submandibular gland : mixed gland

Interlobular septum

parenchyma

Fig. 2 Submandibular gland(HE stain,high mag.) ①Mixed acinus②Serous acinus

①

②serous demilune

Intercalated duct

Fig.3 Submandibular gland(HE stain,high mag.) ①mucous acinus ②Serous acinus

①

②

Fig.4 Submandibular gland(HE stain,high mag.) ①Secretory duct ②Serous acinus

① ②

Fig.5 Submandibular gland (HE stain,high mag.)

Intralobular duct

The pancreas can be divided into two portion:

exocrine portion and endocrine portion. The exocri

ne portion is a serous, compound tubloacinar gland.

The endocrine portion is called pancreatic islet( is

let of Langerhans).

Fig. 6 Pancreas (HE stain, low mag.) pancreatic islet exocrine portion① ②

①

②

①

Fig .7 Pancreas (HE stain, high mag.) centroacinar cells

Fig. 8 Pancreas(HE stain, high mag.) pancreatic islet exocrine portion① ②

①

②

Fig . 9 A cell of pancreatic islet (TEM) nucleus secretory granule① ②

The cells secrete glucagon.

①

②

Fig. 10 B-cell of pancreas islet(TEM) nucleus secretory granule① ②

The B cells secrete insulin.

①

②

The liver is the biggest gland in the body. It c

an be divided into two main parts: hepatic lobule

and portal area.

The hepatic lobule includes five components :

central vein, hepatic plate(cord), hepatic sinusoid,

perisinusoidal space and bile canaliculi.

Hepatic lobule

Portal areas

Fig. 11 Liver of pig (HE stain, low mag.)

Central vein

Hepatic cord

Hepatic sinusoid

Fig. 12 hepatic lobule (HE stain, high mag.)

Hepatocyte

Hepatocyte

Fat- storing cell

Fig. 13 Portal area of liver(HE stain , high mag.)

①interlobular artery interlobular vein interlobular bile duct② ③

①

② ③

Central vein

Central vein

Fig. 14 Liver of human (HE stain, low mag.)

Hepatic macrophage

Fig. 15 Liver of mouse (trypan blue injected preparation, high mag.)

Hepatic macrophage

Fig. 16 Hepatic macrophage in hepatic sinusoid (SEM)

bile canaliculus

Central vein

Fig. 17 liver(silver stain, low mag.) showing bile canaliculus

Fig. 18 liver (silver stain, high mag.) showing bile canaliculus

bile canaliculus

Fig.19 gall bladder (HE, low mag.)

plica

Three layers : mucous membrane, muscularis and serosa.

Fig.20 gall bladder

(HE, low mag.)

Simple columnar epithelium