Digestive System PDF

Digestive System  Digestive System ♣ Consists of digestive tract and associated glands ♣ The digestive tract consists of mouth, pharynx, esophagus, stomach, small intestine and large intestine ♣ The digestive glands include; salivary glands, liver, gall bladder and pancreas ...

Digestive System  Digestive System ♣ Consists of digestive tract and associated glands ♣ The digestive tract consists of mouth, pharynx, esophagus, stomach, small intestine and large intestine ♣ The digestive glands include; salivary glands, liver, gall bladder and pancreas  Alimentary Canal Alimentary canal ( gastrointestinal tract) is a hollow muscular tube and is opened at both ends.  1- Mouth (oral cavity) Is a mucus membrane lined cavity. Lips protect its anterior opening,. The cheeks form its lateral walls. The palate forms its roof. The tongue is attached to the floor of the mouth. ♣ The mouth cavity proper has Roof and Floor Roof : Hard and soft palate. Floor: Tongue. contains tongue, teeth, sublingual glands and openings of salivary ducts 2- The Pharynx The oral cavity ends into the oropharynx The oropharynx continues as laryngopharynx which leads to esophagus 3-Esophagus ♣ 25 cm long muscular tube begins from the end of pharynx and ends in the stomach. ♣ It has cervical, thoracic and short abdominal parts ♣ It delivers the ingested food from pharynx to stomach by peristalsis movement  4- The Stomach ♣ Begins at the cardiac opening and ends at the pyloric opening fundus (junction) with duodenum. cardia ♣ It is descriptively divided into; Lessor omentum cardia, fundus, body, antrum body & pyloric canal Pyloric antrum Greater omentum 4- Stomach 10  Small intestine Is the longest portion of alimentary canal (6 meters) Is of three parts: duodenum, jejunum, ileum. It starts at pylorus and ends at iliocecal junction. Duodenum is 25 cm long, It receives the opening of bile duct and pancreatic ducts. Most of absorption of food happens in small intestine. The surface area of small intestine is increased by presence of microvilli and villi Plicea circularis are large circular folds of mucosa and submucosa. Peyers patches are lymphoid nodules in the submucosa of distal parts of small intestine  5- The Small Intestine 5-6 m long, consists of Duodenum Jejunum and Ileum  A-Duodenum ♣ It has the openings of bile and pancreatic ducts ♣ it digests the food particles by bile from liver, and pancreatic enzymes.  Large intestine Larger in diameter than small intestine but much shorter. It extends from the iliocecal junction to the anal canal Parts of the Large Intestine: - Cecum - Appendix - Ascending colon - Transverse colon - Descending colon - Sigmoid colon - Rectum - Anal canal  The main function of large intestine is to absorb water and electrolytes and to store the residues of digestion and its elimination from the body as feces. Appendix is commonly inflamed and infected (appendicitis) and then appendectomy may be necessary.  6- The Large Intestine ♣ 1.5 m long, surround the coils of small intestine Consists of 4- Transverse colon Right colic (hepatic) Left colic (splenic) flexure flexure 3- Ascending colon 5- Descending colon Ileum 1- Cecum , 6- Sigmoid colon 2- Appendix 7- Rectum 8- Anal canal 9- Anus Associated digestive Glands 1- The Salivary Glands ♣ Include three pairs; Parotid Sublingual and Submandibular ♣ Their ducts open in the oral cavity  The Teeth The deciduous teeth of childhood are 20; The permanent teeth are 32 The Tongue A mass of skeletal muscles covered by mucus membrane, located in oral cavity and oropharynx.  The Pancreas Is a soft, pink triangular gland located on the posterior abdominal wall. It produces digestive enzymes which are secreted into the duodenum. It is also an endocrine gland secreting insuline and glucagon.  The Pancreas ♣ Large gland surrounded by duodenum ♣ It is an endocrine and exocrine Divided into Head, Neck, Tail Body and Tail Body Neck Head  Liver Liver is the largest gland in the body. It is located under the diaphragm, more to the right side of the body It has many metabolic functions. The digestive function of liver is by secretion of bile through the biliary ducts to the duodenum. The liver lobes are: Right lobe Left lobe Caudate lobe Quadrate lobe.  3- The Liver & Gall Bladder ♣ The liver is large organ ♣ Anteriorly right and left lobes By the Falciform lig Visceral surface The right is subdivided into quadrate lobe quadrate lobe and a caudate lobe by the ligamentum teres, gallbladder the inferior vena cava, and liqamentum venosum caudate lobe  Gall bladder Gall bladder is a small thin walled green sac. Right and left hepatic ducts unites to form the common hepatic duct which unites with the cystic duct to form the common bile duct. Common bile duct opens in the duodenum. 4- Gall bladder ♣ is muscular sac attached to inferior of visceral surface of liver common hepatic duct cystic duct neck body The gallbladder is divided into the fundus, body, and neck. fundus ♣ Its duct is called cystic duct joins common bile duct to form common bile duct  Peritoneum Is the largest serous membrane in the body. Parietal peritoneum is that portion of peritoneum that lines the walls of abdominopelvic cavity. Visceral peritoneum covers the organs. The slim space between visceral and parietal peritoneum is called peritoneal cavity which contains peritoneal fluid. Ascitis is accumulation of excess fluid inside the peritoneal cavity.  There are five major peritoneal folds: the greater omentum, falciform ligament, lesser omentum, mesentery, and mesocolon..and others.