10.digestive Gland

The extrinsic glands of the digestive system include the major salivary glands, the pancreas, and the liver, all of which are located outside the wall of the digestive tract. The major salivary glands consist of three pair of glands: the parotid, submandibular glands and sublingual glands.

Interlobula r septum

parenchyma

Specimen NO.43

Submandibular gland : mixed gland

HE

① serous demilune

②

Specimen NO.43 Submandibular gland ①Mixed acinus ②Serous acinus

Intercalated duct

①

②

Specimen NO.43

Submandibular gland ①mucous acinus ②Serous acinus

①

Specimen NO.43

Submandibular gland

②

①Secretory duct ②Serous acinus

Small vein

Intralobular duct

Specimen NO.43

Submandibular gland

The pancreas can be divided into two portion: exocrine portion and endocrine portion. The exocrine portion is a serous, compound tubloacinar gland. The endocrine portion is called pancreatic islet( islet of Langerhans).

② ①

① Specimen NO.46

Pancreas ①pancreatic islet ②exocrine portion HE

Specimen NO.46

Pancreas

centroacinar cells(

)

①

②

Specimen NO.46

Pancreas ①Pancreatic islet ②Exocrine portion

②

①

A cell of pancreatic islet ①Nucleus ②Secretory granule The cells secrete glucagon.

(TEM)

①

②

①Nucleus ②Secretory granule The B cells secrete insulin. (TEM)

B-cell of pancreatic islet

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

Specimen NO.47

Liver of pig

HE stain

Hepatic sinusoid Hepatic cord

Central vein

Specimen NO.47

Liver of pig showing hepatic lobule

HE s

Hepatocyte

Hepatocyte

Fat- storing cell

②

③ ①

Specimen NO.47 ①Interlobular artery

Liver of pig showing Portal area of liver ②Interlobular vein ③ Interlobular bile duct

Central vein

Central vein

Specimen NO.48

Liver of human

HE stain

Hepatic macrophage

Hepatic macrophage

Specimen NO.49

Liver of mouse (trypan blue injected preparation)

Hepatic macrophage in hepatic sinusoid (SEM)

bile canaliculus

Central vein

Specimen NO.50 Liver of mouse showing bile canaliculus. silver stain

bile canaliculus

Specimen NO.50 Liver of mouse showing bile canaliculus silver stain

plica

Three layers : mucous membrane, muscularis and serosa.

Specimen NO.51 gall bladder

HE

Simple columnar epithelium

Specimen NO.51 Gall bladder HE Stain

QUESTIONS 1 ． Describe the general structure of salivary gland. 2 ． What structure features do the acini of pancreas have? 3 ． How many tapes of cells does the pancreas islet include? 4 ． Describe the structure of hepatic lobule.