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1、Small intestine disease,Department of general surgery Yaxu Wang,Chapter 1 Anatomy and Physiology,In this chapter, the normal anatomy and physiology of the small intestine are described, as well as disease processes involving the small bowel, which include: obstruction inflammatory diseases neoplasms
2、,The entire small intestine, which extends from the pylorus to the cecum, measures 300 to 550 cm： duodenal length at about 20 to 35 cm jejunal length at 100 to 110 cm ileal length at 150 to 160 cm.,Chapter 1 Anatomy and Physiology,1.Anatomy 2.Physiology,1.1 Neurovascular-Lymphatic Supply,The small i
3、ntestine is served by rich vascular, neural, and lymphatic supplies, all traversing through the mesentery. The base of the mesentery attaches to the posterior abdominal wall to the left of the second lumbar vertebra and passes obliquely to the right and inferiorly to the right sacroiliac joint.,Chap
4、ter 1 Anatomy and Physiology,1.Anatomy,1.1 Neurovascular-Lymphatic Supply,The blood supply of the small bowel, except for the proximal duodenum that is supplied by branches of the celiac axis, comes entirely from the superior mesenteric artery.,Chapter 1 Anatomy and Physiology,1.Anatomy,1.1 Neurovas
5、cular-Lymphatic Supply,The blood supply of the small bowel, except for the proximal duodenum that is supplied by branches of the celiac axis, comes entirely from the superior mesenteric artery.,Chapter 1 Anatomy and Physiology,1.Anatomy,1.1 Neurovascular-Lymphatic Supply,The superior mesenteric arte
6、ry courses anterior to the uncinate process of the pancreas and the third portion of the duodenum, where it divides to supply the pancreas, distal duodenum, entire small intestine, and ascending and transverse colon. Venous drainage of the small bowel parallels the arterial supply, with blood draini
7、ng into the superior mesenteric vein, which joins the splenic vein,then to the the portal vein . The innervation of the small bowel is provided by both parasympathetic and sympathetic divisions of the autonomic nervous system, which in turn provide the efferent nerves to the small intestine.,Chapter
8、 1 Anatomy and Physiology,1.Anatomy,1.2 Microscopic Anatomy,The small bowel wall consists of four layers: serosa muscularis propria submucosa mucosa,Chapter 1 Anatomy and Physiology,1.Anatomy,Chapter 1 Anatomy and Physiology,1.Anatomy 2.Physiology,Digestion and Absorption Function The complex proces
9、s of digestion and eventual absorption of nutrients, water, electrolytes, and minerals is the main role of the small intestine. The small bowel is primarily responsible for absorption of the dietary components (carbohydrates, proteins, and fats), as well as ions, vitamins, and water. Endocrine Funct
10、ion In fact, the small bowel is the largest endocrine organ in the body. Immune Function The small intestine serves as a major immunologic barrier in addition to its important role in digestion and endocrine function. As a result of constant antigenic exposure, the intestine possesses abundant lymph
11、oid cells (i.e., B and T lymphocytes) and myeloid cells (macrophages, neutrophils, eosinophils, and mast cells). To deal with the constant barrage of potential toxins and antigens, the gut has evolved into a highly organized and efficient mechanism for antigen processing, humoral immunity, and cellu
12、lar immunity.,Chapter 2 Inflammatory diseases,1.Crohns Disease 2.Tuberculosis of intestine 3.Typhoid enteritis 4.Acute hemorrhagic enteritis,1.Crohns Disease,Crohns disease is a chronic, transmural inflammatory disease of the gastrointestinal tract of unknown cause. Although Crohns disease most comm
13、only affects the end of the small intestine (the ileum) and the beginning of the large intestine (the colon), it may involve any part of the GI tract.,Chapter 2 Inflammatory diseases,1.Crohns Disease,The disease is named after Dr. Burrill B. Crohn in 1932.Crohns and a related disease, ulcerative col
14、itis, are the two main disease categories that belong to a larger group of illnesses called inflammatory bowel disease (IBD). Because the symptoms of these two illnesses are so similar, it is sometimes difficult to establish the diagnosis definitively.,Chapter 2 Inflammatory diseases,1.Crohns Diseas
15、e,Chapter 2 Inflammatory diseases,1.1 Incidence and Epidemiology,Crohns disease is the most common primary surgical disease of the small bowel, with an annual incidence of 3 to 7 cases per 100,000 of the general population; the incidence is highest in North America and Northern Europe. Crohns diseas
16、e primarily attacks young adults in the second and third decades of life. The risk for developing Crohns disease is about two times higher in smokers than in nonsmokers. Although Crohns disease is uncommon in African blacks, blacks in the United States have rates similar to whites. Certain ethnic groups, particularly Jews, have a greater incidence of Crohns disease than do age- and gender-matched control subjects.,1.Crohns Disease,Chapter 2 Inflammatory diseases,1.2 Etiology
