Human Anatomy Lecture 14: Gastrointestinal System (2022-2023 PDF)

Academic year 2022-2023 ‫فرع جراحة الفم والوجه والفكين‬ ‫كلية طب االسنان‬ 1st year Human Anatomy Lecture 14...

Academic year 2022-2023 ‫فرع جراحة الفم والوجه والفكين‬ ‫كلية طب االسنان‬ 1st year Human Anatomy Lecture 14 GASTROINTESTINAL SYSTEM By:Dr.Nada hashim AL JASSIM Snell R.S. Clinical Anatomy by regions, 9th Edition, Lippincott Williams & Wilkins,2012 For more detailed instructions, any question, cases need help please post to the telegram group of the session Anatomy of gastrointestinal tract Digestive System The digestive system Composed of gastrointestinal tract (GIT) or (Alimentary canal) and accessory organs. 1.Alimentary canal – mouth, pharynx, esophagus, stomach, small intestine, and large intestine 2.Accessory digestive organs – teeth, tongue, gallbladder, salivary glands, liver, and pancreas. The major organs of the digestive system are the stomach and intestine. upper gastrointestinal tract: This tract consists of the esophagus, stomach, and duodenum. lower gastrointestinal tract: This tract includes most of the small intestine and all of the large intestine. Digestive juices are produced by the pancreas and the gallbladder.  The small intestine includes the duodenum, jejunum, and ileum.  The large intestine includes the cecum, colon, rectum, and anus. Accessory of GIT: The accessory organs include the teeth, tongue, and glandular organs such as salivary glands, liver, gallbladder, and pancreas. The upper gastrointestinal tract includes : the Esophagus, the fibromuscular tube that food passes through—aided by peristaltic contractions—the pharynx to the stomach. Stomach, which secretes protein - digesting enzymes called proteases and strong acids to aid in food digestion, before sending the partially digested food to the small intestines. Duodenum, the first section of the small intestine that may be the principal site for iron absorption Lower Gastrointestinal Tract :The lower gastrointestinal tract includes most of the small intestine and all of the large intestine. According to some sources, it also includes the anus. The small intestine has three parts: Duodenum: Here the digestive juices from the pancreas ( digestive enzymes ) and the gallbladder ( bile ) mix together. The digestive enzymes break down proteins and bile and emulsify fats into micelles. The duodenum contains Brunner’s glands that produce bicarbonate, and pancreatic juice that contains bicarbonate to neutralize hydrochloric acid in the stomach. Jejunum: This is the midsection of the intestine, connecting the duodenum to the ileum. It contains microvilli to increase the surface area of that part of the GI tract. Ileum: This has villi, where all soluble molecules are absorbed into the blood ( through the capillaries and lacteals). The large intestine has four parts:  Cecum, the vermiform appendix that is attached to the cecum.  Colon, which includes the ascending colon, transverse colon, descending colon, and sigmoid flexure. The main function of the colon is to absorb water, but it also contains bacteria that produce beneficial vitamins like vitamin K  Rectum.  Anus