组胚2012级临床医学消化管

1、第章消化管Digestive tract消化系统组成 消化管 消化腺消化系统功能 消化吸收 免疫 内分泌消化管壁的一般结构： 1 黏膜mucosa 上皮epithelium 固有层lamina propria黏膜肌层muscularis mucosa 2黏膜下层submucosa 食管腺和十二指肠腺 皱襞plica 3 肌层muscularis 内环、外纵两层 神经丛 4 外膜adventitia 纤维膜fibrosa 浆膜serosa 食管esophagus 黏膜:未角化复层扁平上皮,黏液性腺泡,黏膜肌层为一层纵行平滑肌 黏膜下层:食管腺 肌层:内环、外纵,骨骼肌向平滑肌过渡 外膜:纤维膜

2、胃 1黏膜：上皮为单层柱状上皮,主要为表面黏液细胞surface mucous cell,参与黏液碳酸氢盐屏障的生成.固有层含胃底腺、贲门腺和幽门腺;黏膜肌层为内环外纵两层. 胃小区gastric area,胃小凹gastric pit, 2黏膜下层:较致密结缔组织 营养血管 淋巴管 神经等 3 肌层:内斜、中环、外纵三层 4 外膜:为浆膜 胃底腺fundic gland,或称泌酸腺oxyntic gland 分部 峡、颈、底三部 细胞有主细胞、壁细胞、颈黏液细胞、干细胞和内分泌细胞. 1 主细胞chief cell 又称胃酶细胞zymogenic cell,柱状,多集中于腺体底部,胞质基部嗜

3、碱染色. 功能 分泌胃蛋白酶原pepsinogen2 壁细胞parietal cell（泌酸细胞oxyntic cell) 以胃底腺峡、颈部较多 胞质嗜酸染色 电镜结构 细胞内分泌小管intracellular secretory canaliculus、微管泡系统tubulovesicular system、线粒体 功能: 合成和分泌盐酸 分泌内因子intrinsic factor3 颈黏液细胞mucous neck cell 染色淡，分泌酸性黏液4 干细胞stem cell 可分化为其它的胃底腺细胞5 内分泌细胞 ECL细胞 分泌组胺 D细胞 分泌生长抑素 小 肠 一黏膜 环行皱襞、肠绒毛

4、intestinal villus、小肠腺small intestinal gland 单层柱状上皮覆盖肠绒毛表面并构成肠腺 肠腺细胞组成：吸收细胞absorptive cell、杯状细胞goblet cell、潘氏细胞Paneth cell、干细胞、内分泌细胞 固有层:肠腺,多种结缔组织细胞,中央乳糜管,淋巴小结. 黏膜肌层:内环、外纵平滑肌.二 黏膜下层:在十二指肠段此层有肠腺三 肌层:内环，外纵平滑肌四 外膜：主要为浆膜 大 肠Large intestine一黏膜：上皮为单层柱状，细胞成份：吸收细胞、杯状细胞（数量较小肠多），固有层有大量大肠腺和淋巴组织二黏膜下层：结构同小肠三 肌层：内

5、环、外纵 参与结肠袋（带）的构成四 外膜：浆膜或纤维膜 消化管的淋巴组织及其免疫功能 1 消化液的防御功能 2 淋巴组织和免疫细胞的免疫功能 3 微皱褶细胞microfold cell， M细胞 4 分泌型IgA secretory IgA sIgA 胃肠的内分泌细胞 胃肠内分泌细胞的特点 分散存在 种类多 总量大 所分泌的激素除调节消化管消化功能以外 也参与调节其它器官的生理活动 细胞类型分开放型和封闭型 激素类型多为肽类或胺类。 作用方式 血循环、旁分泌The digestive tract extending from the esophagus to the large intesti

6、ne is made up of four concentric layers, exhibiting considerable regularity. Named in order from the lumen outward, these are the mucosa, submucosa, muscularis externa, and adventitia or serosa.The mucosa, or mucous membrane, has three components: superficial epithelium, lamina propria and musculari

7、s mucosa. The muscularis mucosa is subdivided into an inner circular and an outer longitudinal layer. Large accumulations of typical lymphatic tissues are often present in the stroma. The entire lamina propria of most segments of the gut is a major site of immunologic response. The mucosa projects i

8、nto the lumen as folds or villi. These invaginations and evaginations of the lining of the gut increase its effective surface area tremendously. The mucosa differs considerably from segment to segment of the alimentary tract in relation to the changing functional activity. Considerable emphasis will

9、 be placed in the following descriptions on the specialized mucosa cells involved in secretion and absorption. The submucosa is a connective tissue layer, often containing accumulations of lymphatic tissue as well as glands that extend from the mucosa. The muscularis externa contains at least two la

10、yers of muscle. The muscle is smooth in all parts except for the upper esophagus and the anal sphincter,where it is composed of skeletal muscle fibers. The muscle fibers of the inner layer are arranged in a circular manner while that of the outer layer are longitudinal. Contraction of the circular layer constricts the lumen whereas contraction of the longitudinal layer shortens the tube. The adventitia is made