Chapter 14 Digestive gland

---small gland: fundis gland, small intestinal gland ---large gland: salivary gland, pancreas, liver

1. Pancreas

胰腺-图

---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（胰蛋白酶原） amylase（淀粉酶） lipase（脂酶） chymotrypsinogen （糜蛋白酶原）

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.

a.   A cell: 20%. Large polygonal in shaped, peripheral-distributed EM: secretory G: large, 190-310 nm, round with dense core function: secret glucogon（高血糖素） - 29 amino acid residues protein ↓ glycogen→ glucose

A cell

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

B cell

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（生长抑素） to inhibit the secreting of A, B, PP cell

d. PP cell: EM: secrete granule: small, 110-170 nm function: secrete pancreatic polypeptide （胰多肽）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，血管活性肠肽) f. C cell: undifferentiated cell

肝-图 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 (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氧化还原酶 (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（胆红素） microbody: -round, 0.2-1.0 um -contain catalase （过氧化氢酶）and peroxidase（过氧化物酶） 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:

9-12 um endothelial cell: fenestrated, gap, plasmalemmal vesicles -liver macrophage (Kupffer cell) -large granular lymphocyte: NK cell

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 ) ｛

Blood circulation of liver 血窦 中央V 小叶下V 肝A 小叶间A 终末肝微A 肝V

4) Passage of bile 肝细胞 胆小管 闰管 小叶间胆管 左右肝管 肝总管 胆囊管 胆囊 或经胆总管到十二指肠

谢谢！