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The Anatomy of the Rectum and Anal Canal
BASIC SCIENCE identify the rectosigmoid junction with confidence at operation. The anatomy of the rectum The rectosigmoid junction usually lies approximately 6 cm below the level of the sacral promontory. Approached from the distal and anal canal end, however, as when performing a rigid or flexible sigmoid- oscopy, the rectosigmoid junction is seen to be 14e18 cm from Vishy Mahadevan the anal verge, and 18 cm is usually taken as the measurement for audit purposes. The rectum in the adult measures 10e14 cm in length. Abstract Diseases of the rectum and anal canal, both benign and malignant, Relationship of the peritoneum to the rectum account for a very large part of colorectal surgical practice in the UK. Unlike the transverse colon and sigmoid colon, the rectum lacks This article emphasizes the surgically-relevant aspects of the anatomy a mesentery (Figure 1). The posterior aspect of the rectum is thus of the rectum and anal canal. entirely free of a peritoneal covering. In this respect the rectum resembles the ascending and descending segments of the colon, Keywords Anal cushions; inferior hypogastric plexus; internal and and all of these segments may be therefore be spoken of as external anal sphincters; lymphatic drainage of rectum and anal canal; retroperitoneal. The precise relationship of the peritoneum to the mesorectum; perineum; rectal blood supply rectum is as follows: the upper third of the rectum is covered by peritoneum on its anterior and lateral surfaces; the middle third of the rectum is covered by peritoneum only on its anterior 1 The rectum is the direct continuation of the sigmoid colon and surface while the lower third of the rectum is below the level of commences in front of the body of the third sacral vertebra. -
Crohn's Disease of the Colon
Gut, 1968, 9, 164-176 Gut: first published as 10.1136/gut.9.2.164 on 1 April 1968. Downloaded from Crohn's disease of the colon V. J. McGOVERN AND S. J. M. GOULSTON From the Royal Prince Alfred Hospital, Sydney, Australia The fact that Crohn's disease may involve the colon never affected unless there had been surgical inter- either initially or in association with small bowel ference. There was no overt manifestation of mal- disease is now firmly established due largely to the absorption in any of these patients. evidence presented by Lockhart-Mummery and In 18 cases the colon alone was involved. Five had Morson (1960, 1964) and Marshak, Lindner, and universal involvement, five total involvement with Janowitz (1966). This entity is clearly distinct from sparing of the rectum, two involvement of the ulcerative colitis and other forms of colonic disease. descending colon only, two the transverse colon only, Our own experience with this disorder reveals many and in the other four there was variable involvement similarities with that published from the U.K. and of areas of large bowel (Fig. 2). the U.S.A. Thirty patients with Crohn's disease involving the large bowel were seen at the Royal CLINICAL FEATURES Prince Alfred Hospital during the last decade, the majority during the past five years. The criteria for The age incidence varied from 6 to 69 years when the inclusion were based on histological examination of patient was first seen, the majority being between the operative specimens in 28 and on clinical and radio- ages of 11 and 50. -
The Digestive System
Connective tissue The Digestive System Part 1 Structure of digestive system Functions Basic Structure of the Alimentary Canal Wall Tube is made up of four layers: 1. Mucosa 2. Submucosa 3. Muscularis externa 4. Serosa (Peritoneum) or Adventitia Mucosa The innermost wall of the alimentary tube. Consists of: • Epithelium - usually simple columnar epithelium with goblet cells; may be stratified squamous if protection is needed (e.g. esophagus) • Lamina propria – loose connective tissue • Muscularis mucosae – takes part in the formation of folds Submucosa Made up of loose connective tissue. Contains submucosal (Meissner’s) nervous plexus and blood vessels, sometimes glands. Muscularis externa Usually two layers of smooth muscle: • inner circular layer • outer longitudinal layer. • Myenteric (Auerbach’s) nervous plexus in between • Responsible for peristalsis (controlled by the nerve plexus) Outer membrane • A serous membrane/peritoneum consisting of the mesothelium (simple squamous epithelium), and a small amount of underlying loose connective tissue. • Or adventitia consisting only of connective tissue is found where the wall of the tube is directly attached or fixed to adjoining structures (i.e., body wall and certain organs). Enteric nervous system The Alimentary Canal Pharynx Common respiratory and digestive pathway (both air and swallowed food and drinks pass through). • Stratified squamous non-keratinized epithelium • Lamina propria contains many elastic fibers • No muscularis mucosae • No submucosa • Striated muscle in the muscularis externa Esophagus Fixed muscular tube that delivers food and liquid from the pharynx to the stomach. Esophagus Epithelium - stratified squamous Mucosal and submucosal glands of the esophagus secrete mucus to lubricate and protect the luminal wall. Esophageal glands proper lie in the submucosa. -
Vestibule Lingual Frenulum Tongue Hyoid Bone Trachea (A) Soft Palate
Mouth (oral cavity) Parotid gland Tongue Sublingual gland Salivary Submandibular glands gland Esophagus Pharynx Stomach Pancreas (Spleen) Liver Gallbladder Transverse colon Duodenum Descending colon Small Jejunum Ascending colon intestine Ileum Large Cecum intestine Sigmoid colon Rectum Appendix Anus Anal canal © 2018 Pearson Education, Inc. 1 Nasopharynx Hard palate Soft palate Oral cavity Uvula Lips (labia) Palatine tonsil Vestibule Lingual tonsil Oropharynx Lingual frenulum Epiglottis Tongue Laryngopharynx Hyoid bone Esophagus Trachea (a) © 2018 Pearson Education, Inc. 2 Upper lip Gingivae Hard palate (gums) Soft palate Uvula Palatine tonsil Oropharynx Tongue (b) © 2018 Pearson Education, Inc. 3 Nasopharynx Hard palate Soft palate Oral cavity Uvula Lips (labia) Palatine tonsil Vestibule Lingual tonsil Oropharynx Lingual frenulum Epiglottis Tongue Laryngopharynx Hyoid bone Esophagus Trachea (a) © 2018 Pearson Education, Inc. 4 Visceral peritoneum Intrinsic nerve plexuses • Myenteric nerve plexus • Submucosal nerve plexus Submucosal glands Mucosa • Surface epithelium • Lamina propria • Muscle layer Submucosa Muscularis externa • Longitudinal muscle layer • Circular muscle layer Serosa (visceral peritoneum) Nerve Gland in Lumen Artery mucosa Mesentery Vein Duct oF gland Lymphoid tissue outside alimentary canal © 2018 Pearson Education, Inc. 5 Diaphragm Falciform ligament Lesser Liver omentum Spleen Pancreas Gallbladder Stomach Duodenum Visceral peritoneum Transverse colon Greater omentum Mesenteries Parietal peritoneum Small intestine Peritoneal cavity Uterus Large intestine Cecum Rectum Anus Urinary bladder (a) (b) © 2018 Pearson Education, Inc. 6 Cardia Fundus Esophagus Muscularis Serosa externa • Longitudinal layer • Circular layer • Oblique layer Body Lesser Rugae curvature of Pylorus mucosa Greater curvature Duodenum Pyloric Pyloric sphincter antrum (a) (valve) © 2018 Pearson Education, Inc. 7 Fundus Body Rugae of mucosa Pyloric Pyloric (b) sphincter antrum © 2018 Pearson Education, Inc. -
The Small and Large Intestines∗
OpenStax-CNX module: m46512 1 The Small and Large Intestines∗ OpenStax College This work is produced by OpenStax-CNX and licensed under the Creative Commons Attribution License 3.0y Abstract By the end of this section, you will be able to: • Compare and contrast the location and gross anatomy of the small and large intestines • Identify three main adaptations of the small intestine wall that increase its absorptive capacity • Describe the mechanical and chemical digestion of chyme upon its release into the small intestine • List three features unique to the wall of the large intestine and identify their contributions to its function • Identify the benecial roles of the bacterial ora in digestive system functioning • Trace the pathway of food waste from its point of entry into the large intestine through its exit from the body as feces The word intestine is derived from a Latin root meaning internal, and indeed, the two organs together nearly ll the interior of the abdominal cavity. In addition, called the small and large bowel, or colloquially the guts, they constitute the greatest mass and length of the alimentary canal and, with the exception of ingestion, perform all digestive system functions. 1 The Small Intestine Chyme released from the stomach enters the small intestine, which is the primary digestive organ in the body. Not only is this where most digestion occurs, it is also where practically all absorption occurs. The longest part of the alimentary canal, the small intestine is about 3.05 meters (10 feet) long in a living person (but about twice as long in a cadaver due to the loss of muscle tone). -
Sporadic (Nonhereditary) Colorectal Cancer: Introduction
Sporadic (Nonhereditary) Colorectal Cancer: Introduction Colorectal cancer affects about 5% of the population, with up to 150,000 new cases per year in the United States alone. Cancer of the large intestine accounts for 21% of all cancers in the US, ranking second only to lung cancer in mortality in both males and females. It is, however, one of the most potentially curable of gastrointestinal cancers. Colorectal cancer is detected through screening procedures or when the patient presents with symptoms. Screening is vital to prevention and should be a part of routine care for adults over the age of 50 who are at average risk. High-risk individuals (those with previous colon cancer , family history of colon cancer , inflammatory bowel disease, or history of colorectal polyps) require careful follow-up. There is great variability in the worldwide incidence and mortality rates. Industrialized nations appear to have the greatest risk while most developing nations have lower rates. Unfortunately, this incidence is on the increase. North America, Western Europe, Australia and New Zealand have high rates for colorectal neoplasms (Figure 2). Figure 1. Location of the colon in the body. Figure 2. Geographic distribution of sporadic colon cancer . Symptoms Colorectal cancer does not usually produce symptoms early in the disease process. Symptoms are dependent upon the site of the primary tumor. Cancers of the proximal colon tend to grow larger than those of the left colon and rectum before they produce symptoms. Abnormal vasculature and trauma from the fecal stream may result in bleeding as the tumor expands in the intestinal lumen. -
6-Physiology of Large Intestine.Pdf
LARGE INTESTINE COLON MOTILITY Color index • Important • Further explanation 1 Contents . Mind map.......................................................3 . Colon Function…………………………………4 . Physiology of Colon Regions……...…………6 . Absorption and Secretion…………………….8 . Types of motility………………………………..9 . Innervation and motility…………………….....11 . Defecation Reflex……………………………..13 . Fecal Incontinence……………………………15 Please check out this link before viewing the file to know if there are any additions/changes or corrections. The same link will be used for all of our work Physiology Edit 2 Mind map 3 COLON FUNCTIONS: Secretions of the Large Intestine: Mucus Secretion. • The mucosa of the large intestine has many crypts of 3 Colon consist of : Lieberkühn. • Absence of villi. • Ascending • Transverse • The epithelial cells contain almost no enzymes. • Descending • Presence of goblet cells that secrete mucus (provides an • Sigmoid adherent medium for holding fecal matter together). • Rectum • Anal canal • Stimulation of the pelvic nerves1 from the spinal cord can cause: Functions of the Large Intestine: o marked increase in mucus secretion. o This occurs along with increase in peristaltic motility 1. Reabsorb water and compact material of the colon. into feces. 2. Absorb vitamins produced by bacteria. • During extreme parasympathetic stimulation, so much 3. Store fecal matter prior to defecation. mucus can be secreted into the large intestine that the person has a bowel movement of ropy2 mucus as often as every 30 minutes; this mucus often contains little or no 1: considered a part of parasympathetic in large intestine . fecal material. 2: resembling a rope in being long, strong, and fibrous 3: anatomical division. 4 ILEOCECAL VALVE It prevents backflow of contents from colon into small intestine. -
Small & Large Intestine
Small & Large Intestine Gastrointestinal block-Anatomy-Lecture 6,7 Editing file Objectives Color guide : Only in boys slides in Green Only in girls slides in Purple important in Red At the end of the lecture, students should be able to: Notes in Grey ● List the different parts of small intestine. ● Describe the anatomy of duodenum, jejunum & ileum regarding: (the shape, length, site of beginning & termination, peritoneal covering, arterial supply & lymphatic drainage) ● Differentiate between each part of duodenum regarding the length, level & relations. ● Differentiate between the jejunum & ileum regarding the characteristic anatomical features of each of them. ● List the different parts of large intestine. ● List the characteristic features of colon. ● Describe the anatomy of different parts of large intestine regarding: (the surface anatomy, peritoneal covering, relations, arterial & nerve supply) Small intestine The small intestine divided into : Fixed Part (No Mesentery): Free (Movable) Part (With Parts Duodenum* Mesentery): Jejunum & Ileum Shape C-shaped loop coiled tube Length 10 inches 6 meters (20 feet) Transverse Colon separates the Beginning At pyloro-duodenal junction at duodeno-jejunal flexure stomach/liver from the jejunum/ileum Termination At duodeno-jejunal flexure at ileo-ceacal flexure Peritoneal Covering Retroperitoneal mesentery of small intestine Divisions 4 parts --------- Foregut (above bile duct opening in 2nd part )& Midgut Embryological origin Midgut (below bile duct opening in 2nd part) So 2nd part has double -
COLON RESECTION (For TUMOR)
GASTROINTESTINAL PATHOLOGY GROSSING GUIDELINES Specimen Type: COLON RESECTION (for TUMOR) Procedure: 1. Measure length and range of diameter or circumference. 2. Describe external surface, noting color, granularity, adhesions, fistula, discontinuous tumor deposits, areas of retraction/puckering, induration, stricture, or perforation. 3. Measure the width of attached mesentery if present. Note any enlarged lymph nodes and thrombosed vessels or other vascular abnormalities. 4. Open the bowel longitudinally along the antimesenteric border, or opposite the tumor if tumor is located on the antimesenteric border, i.e. try to avoid cutting through the tumor. 5. Measure any areas of luminal narrowing or dilation (location, length, diameter or circumference, wall thickness), noting relation to tumor. 6. Describe tumor, noting size, shape, color, consistency, appearance of cut surface, % of circumference of the bowel wall involved by the tumor, depth of invasion through bowel wall, and distance from margins of resection (radial/circumferential margin, mesenteric margin, closest proximal or distal margin). a. If resection includes mesorectum, gross evaluation of the intactness of mesorectum must be included. For rectum, the location of the tumor must also be oriented: anterior, posterior, right lateral, left lateral. b. If a rectal tumor is close to distal margin, the distance of tumor to the distal margin should be measured when specimen is stretched. This is usually done during intraoperative gross consultation when specimen is fresh. c. If the tumor is in a retroperitoneal portion of the bowel (e.g. rectum), radial/retroperitoneal margin must be inked and one or more sections must be obtained (a shave margin, if tumor is far from the radial margin; and perpendicular sections showing the relationship of the tumor to the inked radial margin, if tumor is close to the radial margin). -
Aandp2ch25lecture.Pdf
Chapter 25 Lecture Outline See separate PowerPoint slides for all figures and tables pre- inserted into PowerPoint without notes. Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1 Introduction • Most nutrients we eat cannot be used in existing form – Must be broken down into smaller components before body can make use of them • Digestive system—acts as a disassembly line – To break down nutrients into forms that can be used by the body – To absorb them so they can be distributed to the tissues • Gastroenterology—the study of the digestive tract and the diagnosis and treatment of its disorders 25-2 General Anatomy and Digestive Processes • Expected Learning Outcomes – List the functions and major physiological processes of the digestive system. – Distinguish between mechanical and chemical digestion. – Describe the basic chemical process underlying all chemical digestion, and name the major substrates and products of this process. 25-3 General Anatomy and Digestive Processes (Continued) – List the regions of the digestive tract and the accessory organs of the digestive system. – Identify the layers of the digestive tract and describe its relationship to the peritoneum. – Describe the general neural and chemical controls over digestive function. 25-4 Digestive Function • Digestive system—organ system that processes food, extracts nutrients, and eliminates residue • Five stages of digestion – Ingestion: selective intake of food – Digestion: mechanical and chemical breakdown of food into a form usable by -
Digestive System
Digestive system Dr. Anna L. Kiss Department of Anatomy, Histology and Embryology Semmelweis University Budapest 2019 The gastrointestinal tract (GI tract): digestion and excretion Upper gastrointestinal tract The upper GI tract consists of the mouth, pharynx, esophagus, and stomach. The lower GI tract. small intestine, which has three parts: -duodenum -jejunum -ileum large intestine, which has three parts: -cecum (the vermiform appendix is attached to the cecum). -colon (ascending colon, transverse colon, descending colon and sigmoid flexure) -rectum Primitive Gut Tube Coeliac trunk Superior mesenteric artery Inferior mesenteric artery Vitelline duct Umbilical loop Umbilical artery Final Position of Parts of Gut Tube Abdominal esophagus Thoracic esophagus Liver Stomach Gall bladder & bile duct Duodenum Pancreas 2.) Transverse colon Jejunum & ileum 1.) Ascending colon 3.) Descending colon Cecum Appendix 4.) Sigmoid colon Final Position of Parts of Gut Tube Stomach: left hypochondric region (intraperitoneal) Duodenum: right side (partly retroperitoneal) Jejunum, ileum: umbilical + iliac region (intraperitoneal) Appendix: right side (Mc Burney point) (intraperitoneal) Ascending colon: right iliac region Transverse colon: middle position (intraperitoneal) Descending colon: left iliac region Sigmoid colon: sacral and pelvic region (intraperitoneal) highly acidic environment due to gastric acid production The stomach lies between the esophagus and the duodenum It is on the left side of the abdominal cavity. Stomach fundus cardia rugae!! lesser curvature body pylorus greater curvature Diaphragm Fundus pyloric antrum Corpus superior part body (duodenum) Greater curvature descending part (duodenum) ascending part Jejunum horizontal part Histology of the gut Mucosa: • epithelium: simple columnar (goblet cells) • propria (lymphoreticular connective tissue): glands (Lieberkhün crypts) • muscularis mucosae (2 layered smooth muscle) Submucosa: loose connective tissue (submucosus plexus; glands, lymphatic follicles) External muscle layer (t. -
Colon and Rectum
AJC12 7/14/06 1:24 PM Page 107 12 Colon and Rectum (Sarcomas, lymphomas, and carcinoid tumors of the large intestine or appendix are not included.) C18.0 Cecum C18.5 Splenic flexure of C18.9 Colon, NOS C18.1 Appendix colon C19.9 Rectosigmoid C18.2 Ascending colon C18.6 Descending colon junction C18.3 Hepatic flexure of C18.7 Sigmoid colon C20.9 Rectum, NOS colon C18.8 Overlapping lesion of C18.4 Transverse colon colon SUMMARY OF CHANGES •A revised description of the anatomy of the colon and rectum better delineates the data concerning the boundaries between colon, rectum, and anal canal. Ade- nocarcinomas of the vermiform appendix are classified according to the TNM staging system but should be recorded separately, whereas cancers that occur in the anal canal are staged according to the classification used for the anus. •Smooth extramural nodules of any size in the pericolic or perirectal fat are con- sidered lymph node metastases and will be counted in the N staging. In contrast, irregularly contoured nodules in the peritumoral fat are considered vascular invasion and will be coded as transmural extension in the T category and further denoted as either a V1 (microscopic vascular invasion) if only microscopically visible or a V2 (macroscopic vascular invasion) if grossly visible. • Stage Group II is subdivided into IIA and IIB on the basis of whether the primary tumor is T3 or T4 respectively. • Stage Group III is subdivided into IIIA (T1-2N1M0), IIIB (T3-4N1M0), or IIIC (any TN2M0). INTRODUCTION The TNM classification for carcinomas of the colon and rectum provides more detail than other staging systems.