Large intestine

Anatomy of Large Intestine.

1. LARGE INTESTINE Presented By: M. SHARMIN BANDELI GUIDED BY: Dr. SAPNA HIREMATH N.K.J.AYURVEDIC MEDICAL COLLEGE & P.G. CENTRE, BIDAR.

2. INTRODUCTION: The Large Intestine is located in the abdomen. It is the final section of the Gastrointestinal Tract.

3. It is an Intra peritoneal organ. Its overall function is_ completion of absorption production of certain vitamins formation and expulsion of faeces from the body. It is wider in diameter than small intestine and hence named. It is wider at its commencement and gradually diminishes towards rectum.

4. ANATOMY: The large intestine is about 1.5m long and about 3 inches in diameter. It extends from Ileocecal junction to the anus. Attached to the posterior abdominal wall by its mesocolon . Ileocecal junction is guarded by a fold of mucous membrane called Ileocecal sphincter.

5. Cecum -small pouch- 6cm. Vermiform appendix- twisted,coiled tube- 8cm. Rectum- 20cm Anus- terminal 2-3cm of rectum Mesentry of appendix- Mesoappendix -attaches to inferior part of mesentry of ileum.

6. ILEO CAECAL JUNCTION: Mesentry : Set of continuous tissues that attaches the intestines too the abdominal wall.

7. HISTOLOGY: Wall of the L.I contains 4 layers as found in rest of the G.I Tract. Mucosa Sub mucosa Muscularis Serosa Mucosa- Simple columnar epithelium, lamina propria and muscularis mucosae . Epithelium- Absorptive and goblet cells Goblet cells- mucous-lubrication to colonic contents

8. Both absorptive and goblet cells are present in long, straight, tubular intestinal glands (Crypts of Liberkuhn ) that extend the full thickness of mucosa. Solitary lymphatic nodules- lamina propria of mucosa may extend through the muscularis mucosae into the sub mucosa.

9. Numerous solitary lymphatic follicles are present which provides protection against bacteria present in the lumen of intestine. Lamina Propria : Loose connective tissue; beneath epithelium; together constitute mucosa. Crypts of Liberkuhn : The cells of these gland i.e., Paneth cells secretes intestinal juice. They are spreaded in the lumen of intestine. Mucous membrane and sub mucosa are seperated by a thin layer of muscle called Muscularis mucosae .

10. PARTS: The parts of large intestine are 1. Cecum 2. Colon 3. Flexure 4. Rectum 5. Anus Ascending Transverse Descending Sigmoid Rt. Colic flexure/ Hepatic flexure Lt. Colic flexure/ Splenic flexure

11. COLONS:

12. FLEXURES:

13. BLOOD SUPPLY: Arterial supply is by Marginal artery of Drummond arising from superior and inferior mesentric artery which are the branches of abdominal aorta. Terminal branches are distributed to the intestine as long and short vessels viz., vasa longa and vasa brevia . 1. ARTERIAL SUPPLY:

14. 2. VENOUS DRAINAGE: Venous drainage is by the tributaries of superior and inferior Mesentric vein . This Mesentric veins join the Hepatic Portal Vein .

15. NERVE SUPPLY: Sympathetic and Parasympathetic expect for lower half of anal canal.

16. LYMPHATIC DRAINAGE: Lymph from large intestine passes through 4 sets of lymph nodes 1. Epicolic lymph node 2. Paracolic lymph node 3. Intermediate lymph node 4. Terminal lymph node.

17. FUNCTIONS: The function of the large intestine is to get rid of food left over i.e., bacteria and other wastes after the nutrients are removed from it. This process is called peristalsis.  First, liquid and salt is removed from the waste as it passes through the colon. Then, the waste makes its way to the sigmoid, where it is stored. When the body is ready for a bowel movement, the waste is dumped into the rectum. 

18. CAECUM: Lubricaton to faeces by mucous. Absorption of water, salts and other solutes . ILEOCAECAL VALVE: Prevents reflex from from caecum to ilium . Regulates the passage of ileal contents into caecum . Prevents the contents from passing too quickly.

19. DIFFERENCES BETWEEN SMALL AND LARGE INTESTINE: 4.5-7m long Narrower Villi are present Complicated digestion Secretes no. of hormones Absorbed digested nutrients. 1.5m long Broader Villi are absent No role in digestion No secretion of hormones Absorbs water from undigestable matter. SMALL INTESTINE LARGE INTESTINE

20. APPLIED ANATOMY: Large intestine can be directly viewed by a procedure called Colonoscopy. Due to the evagination of mucous membrane at the entry point of arteries, there is an inflammation called Diverticulitis. Amoebic dysentry in colon. Intestinal tuberculosis and carcinoma.

21. Inflammation of caecum - Caecitis or Typhlitis . Inflammation of appendix- Appendicitis. Appendix is removed by Appendicectomy . McBurney’s Point is a site of maximum tenderness in appendicitis. Appendicular dyspepsia in Chronic Appendicitis.

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