组织学与胚胎学：第十四章 消化管.ppt

第十四章第十四章 消消 化化 管管 (digestive tract)l消化管依次分为口腔、咽、食管、胃、小肠、消化管依次分为口腔、咽、食管、胃、小肠、大肠l消化管与消化腺组成消化系统消化管与消化腺组成消化系统l管壁分四层：粘膜、粘膜下层、肌层、外膜管壁分四层：粘膜、粘膜下层、肌层、外膜一一 消化管一般结构消化管一般结构( (一一) ) 粘膜粘膜(mucosa)(mucosa) 结构差异最大，功能最重要的部分结构差异最大，功能最重要的部分1 1 上皮上皮 1 1）复层扁平上皮）复层扁平上皮 分布：消化管的两端（口腔、咽、食管和分布：消化管的两端（口腔、咽、食管和 肛门）肛门） 功能：保护功能：保护 2 2）单层柱状上皮）单层柱状上皮l分布：胃、小肠、大肠、阑尾分布：胃、小肠、大肠、阑尾l功能：消化、吸收、分泌功能：消化、吸收、分泌2 2 固有层固有层 1 1）结构）结构 l由疏松结缔组织构成由疏松结缔组织构成l毛细血管和毛细淋巴管丰富毛细血管和毛细淋巴管丰富l含单管状腺体，直接开口于管腔，腺体内存含单管状腺体，直接开口于管腔，腺体内存 在干细胞在干细胞l富含淋巴组织。

富含淋巴组织3 3 粘膜肌层粘膜肌层 1 1）结构）结构 ：薄层平滑肌，内环行、外纵行：薄层平滑肌，内环行、外纵行 2 2）功能：促进固有层内腺体分泌物排出和血）功能：促进固有层内腺体分泌物排出和血 液运行，利于物质吸收和转运液运行，利于物质吸收和转运( (二二) )粘膜下层粘膜下层( (submucosa)submucosa)1 1 由结缔组织构成由结缔组织构成2 2 含粘膜下神经丛，由多极神经元和无髓神经含粘膜下神经丛，由多极神经元和无髓神经 纤维组成纤维组成3 3 其他结构：食管腺、十二指肠腺其他结构：食管腺、十二指肠腺( (三三) )肌层肌层（（muscularis)muscularis)1 1 大部分为平滑肌，食管和肛门处含骨大部分为平滑肌，食管和肛门处含骨 骼肌2 2 一般分为内环行、外纵行两层一般分为内环行、外纵行两层3 3 含肌间神经丛，结构类似粘膜下神经含肌间神经丛，结构类似粘膜下神经 丛( (四四) )外膜外膜(adventitia)(adventitia)1 1 浆膜：有间皮浆膜：有间皮2 2 纤维膜：由薄层结缔组织构成纤维膜：由薄层结缔组织构成 二二 食管食管（一）粘膜（一）粘膜 上皮上皮————未角化的复层扁平上皮未角化的复层扁平上皮粘膜肌粘膜肌————一层纵行平滑肌一层纵行平滑肌（二）粘膜下层（二）粘膜下层 食管腺食管腺————粘液性粘液性（三）肌层（三）肌层 平滑肌和骨骼肌平滑肌和骨骼肌（四）纤维膜（四）纤维膜 二二胃胃 （一）粘膜（一）粘膜 1 1 上皮上皮————单柱，表面粘液细胞。

单柱，表面粘液细胞胃小凹胃小凹 功能：分泌粘液，形成粘液功能：分泌粘液，形成粘液——碳酸氢盐屏障碳酸氢盐屏障 2 2 固有层固有层 胃底腺胃底腺 1 1）一般形态）一般形态 分支管状，分支管状， 分分 峡、颈、峡、颈、 底底2 2）细胞组成）细胞组成 l壁细胞（泌酸细胞）壁细胞（泌酸细胞）LMLM：圆锥形，核圆居中，胞质强嗜酸性圆锥形，核圆居中，胞质强嗜酸性EMEM：细胞内分泌小管，微管泡系统，：细胞内分泌小管，微管泡系统，MITMIT功能：分泌盐酸和内因子功能：分泌盐酸和内因子壁细胞壁细胞TEMØ主细胞（胃酶细胞）主细胞（胃酶细胞）LMLM：柱状，核圆近基部，基部胞质嗜碱性柱状，核圆近基部，基部胞质嗜碱性EMEM：：RERRER，，GOLGOL，酶原颗粒，酶原颗粒功能：分泌胃蛋白酶原功能：分泌胃蛋白酶原Ø颈粘液细胞：颈部，分泌粘液颈粘液细胞：颈部，分泌粘液Ø 内分泌细胞：内分泌细胞：ECL---ECL---组胺，组胺，D---D---生长抑素生长抑素Ø干细胞：干细胞：贲门腺：粘液腺贲门腺：粘液腺幽门腺：粘液腺，壁细胞，幽门腺：粘液腺，壁细胞，G G细胞细胞（二）粘膜下层（二）粘膜下层（三）肌层（三）肌层 内斜、中环、外纵平滑肌内斜、中环、外纵平滑肌（四）浆膜（四）浆膜四四 小肠小肠（一）粘膜（一）粘膜特殊结构特殊结构 环行皱襞：粘膜层环行皱襞：粘膜层+ +粘膜下层粘膜下层 绒毛：绒毛： 上皮上皮+ +固有层固有层 微绒毛：胞膜微绒毛：胞膜+ +胞质胞质意义：扩大内表面积意义：扩大内表面积1 1 上皮上皮Ø吸收细胞吸收细胞LMLM：高柱状，核位于基部。

纹状缘高柱状，核位于基部EMEM：： 微绒毛，细胞衣，微绒毛，细胞衣，SERSER，紧密连接紧密连接功能：消化吸收，功能：消化吸收， 参与参与SIgASIgA的释放，的释放， 分泌肠致活酶分泌肠致活酶Ø杯状细胞杯状细胞Ø内分泌细胞内分泌细胞小肠吸收细胞小肠吸收细胞2 2 固有层固有层 1 1）小肠腺）小肠腺 上述三种上述三种C C以及以及Ø潘氏潘氏C C LMLM：锥体形，粗大嗜酸性分泌颗粒锥体形，粗大嗜酸性分泌颗粒功能：分泌防御素、溶菌酶等功能：分泌防御素、溶菌酶等Ø干干C C：增殖分化为其他细胞：增殖分化为其他细胞2 2）淋巴组织）淋巴组织 12 12指指————空空————回肠回肠 孤立孤立LN LN 集合集合LNLN3 3）绒毛中轴）绒毛中轴 内含有中央乳糜管、内含有中央乳糜管、CapCap、少、少 量平滑肌。

量平滑肌 3 3 粘膜肌粘膜肌（二）粘膜下层（二）粘膜下层 12 12指肠腺指肠腺——分泌碱性粘液、分泌碱性粘液、EGFEGF（三）肌层（三）肌层（四）外膜（四）外膜五五 大大 肠肠 1 1 无环行皱襞无环行皱襞2 2 无绒毛无绒毛3 3 肠腺发达无潘氏细胞肠腺发达无潘氏细胞4 4 杯状细胞丰富杯状细胞丰富 六六 阑阑 尾尾 淋巴组织丰富淋巴组织丰富七七 胃肠的内分泌细胞胃肠的内分泌细胞 重点重点l1 1 消化管壁一般结构消化管壁一般结构l2 2 胃上皮胃上皮LMLM、功能、功能l3 3 胃底腺细胞组成（壁胃底腺细胞组成（壁C C、主、主C C的的LMLM、、 EM EM、功能）、功能）l4 4 小肠腔面三种特殊结构意义小肠腔面三种特殊结构意义l5 5 小肠腺细胞组成、肠绒毛结构特点小肠腺细胞组成、肠绒毛结构特点l6 6 三段小肠特点三段小肠特点l7 7 名词解释名词解释: :肠绒毛肠绒毛CHAPTER 14 DIGESTIVE TRACT OUTLIN The digestive tract extends from the mouth to the anus. Except the oral cavity and pharynx, the different regions of the digestive tract has the same basic stru-ctural organization throughout its length. The wall of the digestive tract consists of four distinctive layers. From the lumen outward, they are (1) mucosa, consisting of a lining epithelium, lamina propria, and a muscularis mucosa, (2) submucosa, (3) muscularis externa, (4) adventitia. The oral mucous membrane is com-posed of a stratified epithelium, suppor-ted by lamina propria . The tongue is a muscular organ covered by mucous membrane. the mucosa of the dorsal surface, however, is modified to form three types of papillae: filiform papillae, fungiform papillae, and circum vallate papillae. Filiform and fungiform papillae have taste buds in the epithelium. The tooth consists of four distinct structural components, the enamel and cementum on the outside, the dentin beneath them, and the pulp in a central pulp cavity. The esophagus has the same layers as the rest of the digestive tract.  The epithelial lining is non- keratinised stratified squamous epithelium . In the submucosa are groups of mucus-secreting glands , the esophageal gland . The mus-cularis externa are skeletal in the upper third of the esophagus. In the middle third, a mixture of striated and smooth muscle, in the lower third, the entire muscular coat is composed of smooth muscle. The ad-ventitia is loose connective tissue.  The stomach is the most dilated part of the digestive tract. The gastric mucosa is lined by simple columnar epithelium. These columnar cells are designated surface mucous cells. Three types of glands are usually found in the gastric mucosa: cardiac, gastric and pyloric gland , Gastric glands are composed of five cell types:  (1)parietal cells are seen under TEM to have an extensive intracellular canalicular system and an elaborate tubulovesicular membrane system, numerous mitochondria with complex cristae are also evident. These cells secrete HCL and intrinsic factor. (2) chief cells are typical protein-secreting cells and secrete pepsin in an inactive precursor form designated pep-sinogen.  (3)mucous neck cells secrete a soluble mucus. (4) endocrine cells secrete their product into the lamina propria. (5) stem cells are relatively small in size, they differentiate into new cells to replace the existing surface epithelial cells of the gastric glands. The muscularis externa of the stomach is relatively thick, with three layers of smooth muscle , a thin serosa covers the outer surface of the stomach.  The small intestine is divided into three segments: duodenum, jejunum and ileum. The intestinal mucosa presents numerous finger-like projections called villi . The fenestrated capillary plexus, central blind-ending lymphatic vessels (central lacteal ) and singles smooth muscle cells are found in the cores of the villi. The intestinal epithelium contains a heterogeneous population of simple columnar cells. They include intestinal absorptive cells, goblet cells, enteroendocrine cells and stem cells. The principle type is the intes-tinal absorptive cells which show promi-nent striated borders (microvilli) at their free surfaces. The primary function of this kind of cells is absorption. The intestinal glands are simple tubular structures that extend from the muscularis mucosa throu-gh the thickness of the lamina propria,where they open to the luminal surface of the intestine at the base of the villi. The simple columnar epithelium lining the gland also contain Paneth cells. The Pane-th cells contain abundant large eosino-philic secretory granules. A conspicuous feature in the submucosa of the duodenum is the presence of duodenal glands which secrete a mucin - containing alkaline fluid.  The four layers characteristic of the alimentary canal are present throu-ghout large intestine. However the mu-cosal epithelium of the large intestine contains large number of goblet cells. Lymphatic nodules may occupy both the mucosa and the submucosa around the entire appendix. 。