Digestive System Anatomy PDF

ANATOMY OF THE DIGESTIVE SYSTEM by Dr/ medhat atta salah  OBJECTIVES At the end of the lecture, students should:  List the components of GIT system.  Know the functions GIT system.  Describe the accessory glands of the digestive system.  Structure of the stomach(...

ANATOMY OF THE DIGESTIVE SYSTEM by Dr/ medhat atta salah  OBJECTIVES At the end of the lecture, students should:  List the components of GIT system.  Know the functions GIT system.  Describe the accessory glands of the digestive system.  Structure of the stomach(surfaces, borders and parts).  Difference between small and large intestine.  Parts of the large intestine. Components of digestive system A – The alimentary canal B- Digestive glands  A – The Alimentary canal 1- mouth. 2- pharynx. 3- esophagus 4- stomach 5- small intestine a- duodenum. b- jejunum. c- ileum.  6- large intestine: a- cecum. b- vermiform appendix. c- ascending colon. d- right colic flexure. e- transverse colon. f- left colic flexure. g- descending colon. h- sigmoid colon. i- rectum. j- anal canal  B- digestive glands: 1- salivary glands 2- liver 3- pancreas   gland  Esophagus  Stomach  Small Intestine  Large Intestine  Mouth The mouth contains the tongue and moist by secretion of salvia. The palate: it is the roof of the mouth. It is :formed of two parts Hard palate: the anterior bony part separates- mouth from nose Soft palate: the posterior muscular part with -.uvula hangin down The Tongue: a muscular organ present in the floor of mouth, it is important for: mastication, sucking , speech and taste sensation  Pharynx A wide funnel–shaped muscular tube, 12-14 cm long. It descends from the base of the skull to esophagus, in front of cervical vertebrae. Parts of pharynx: are three - Nasopharynx: behind nose, receives 2 openings of Eustachian tubes. - Oropharynx: behind the mouth, it contain the tonsil. - Hypopharynx: behind the larynx, continuous with esophagus below.  Esophagus - A narrow muscular tube, 25 cm long. It runs in the neck, chest and abdomen Function: transmission of food and drinks from pharynx to stomach. It is closed except during swallowing. - It begins as the continuation of pharynx. - It enters the abdomen by piercing the RT crus of diaphragm then join the cardiac orifice of the stomach.  Stomach  Position: in the upper left side of abdomen.  Shape: is variable, it may be like the letter J.  Size: variable, according to its food content.  The stomach has: 3 parts: 1- Fundus: above the level of cardiac orifice. 2- Body: the large main part of the stomach 3- Pylorus: the canal the ends by the pyloric sphincter 2 openings: 1- cardiac orifice: by which stomach communicate with oesophagus 2- pyloric orifice: communicate with duodenum. 2 curvatures -Lesser curvature: forms the LT border -Greater curvature: forms the RT border. 2 surfaces Anterior: Related to: liver, diaphragm, ribs & abd. wall. Posterior: Related to: (stomach bed):= diaphragm , spleen, pancreas, transverse colon, LT suprarenal gland, splenic rtery and left kidney.  Small Intestine - A muscular tube, 6 meters long, for digestion and absorption of food. - It is divided into three parts: (A) The duodenum: - Is the firsts part of small intestine. 25 cm long. and is C-shaped, around the head of pancreas. - It consists of four parts: 1st is two inches, 2nd is 3 inches, 3rd is 4 inches and 4th is one inch.  The bile duct and the pancreatic duct open together into the 2nd part of the duodenum.  Large Intestine: The tube is about 180 cm long. It forms a frame around the small intestines. It is divided into 10 parts: 1- Cecum: blind-ended dilated part in right iliac fossa. It joins the ileum. 2- Vermiform appendix: a narrow empty part , descends from the coeoum 3- Ascending colon: a fixed part , ascends in front of right kidney 4- Right colic flexure: lies below the liver. 5- Transverse colon: a movable part, which extends horizontally below the stomach. 6- left colic flexure: lies below the spleen, on the left side. 7- Descending colon: a fixed part, descends in front of left kidney 8- Pelvic (or sigmoid) colon: present in the pelvis, it is S- shaped. 9- Rectum: a dilated part , present in pelvis in front of sacrum. 10- Anal canal: it is the terminal part, ends by the anus by which is an opening surrounded by the anal sphincter.  Difference between small &large intestine: Large intestine Small intestine Large small Caliber 180 cm 6 meters Length: Sacculated smooth The wall form 3 long bands Continuous Longitudinal (taenia coli) muscles Present Absent Fat pouches (appendices epiploicae) Ten Three Parts  The digestive glands A: Salivary glands  There are 3 pairs of exocrine glands.  Function: secretion of saliva, to keep the mouth clean, moist and help in digestion, swallowing and speech.  (a) parotid gland: lies blow the ear.  (b) submandibular gland: lies below the angle of the mandible.  (C) Sublingual gland: lies in the floor of mouth, under the tongue.  B: Liver  The largest gland in the body.  Position: occupies the upper right part of the abdominal cavity. It lies below diaphragm under shelter of the ribs.  - It has 2 surfaces: a- diaphragmatic (under diaphragm), b- visceral (postero-inferior) surface: in contact with: stomach duodenum, colon and right kidney.  - Lobes of liver: i- two main: large right and small left lobes. ii- two accessory: quadrate lobe & caudate lobe: are parts of right lobe.  - Hilum of liver: called porta hepatis, it is the place where hepatic artery, portal vein and bile duct enter the inferior surface of liver.  Biliary system  Small bile ducts between hepatic lobules unite to give right and left hepatic ducts, which come from right and left lobes of liver. At porta hepatis, they fuse together forming the common hepatic duct, which joins the cystic duct (of gall bladder ) to give common bile duct. The latter opens into 2nd part of duodenum  The gall bladder  - A pear-shaped sac, present under the liver. It has 3 parts: fundus, body and neck connected to cystic duct.  - Function: Bile is stored and concentrated in gall bladder.  C: Pancreas - A soft elongated organ, fixed on the posterior abdominal wall, behind the stomach. - Length: 20 cm long. It extends horizontally from duodenum to the spleen - Parts: 4  (head, neck, body, tail): - Head: is surrounded by the duodenum. - Neck: lies behind the pylorus of the stomach - Body: the main part, it has 3 surfaces: anterior, posterior and inferior. - Tail: small part, reach the hilum of the spleen.  Histology of pancreas: The pancreas is divided into 1- lobules, formed of pancreatic cells in groups called acini that has very small ducts. 2- Islets of Langerhans, its cells for insulin hormone and others. - Pancreatic duct open into the 2nd part of duodenum. - Function: a mixed gland: 1- It secretes insulin hormone to blood and 2- secrets pancreatic juice to duodenum.  The peritoneum: is a continuous membrane which lines the abdominal cavity and covers the abdominal organs (abdominal viscera). Formed of visceral layer which is adherent to abdominal viscera, parietal layer which lines the abdominal wall with a peritoneal cavity in between containing thin film of serous fluid. ? 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