胃肠壁的典型结构(纵切图) LUMEN OF GASTROINTESTINAL TRACT Endocrine cells A Mucus cel 黏膜层 MUCOSA 黏膜下层 Major blood and SUBMUCOSA<Submucus lymphatic vessels nerve plexus USCULARIS EXTERNA centeno 肌层 nerve plexus 浆膜 Ducts from extemal xocrine lands ABDOMINAL CAVITY liver, pancreas, salivary FIGURE 17-6 ure of the gast wall in longitudinal section. Not shown are the smaller blood vessels, neural connections between胃肠壁的典型结构（纵切图） 黏膜层 黏膜下层 浆膜 肌层