Digestive System PDF

Digestive System Dr. Noha Mohamed Gaber Lecturer of Anatomy & Embryology Ain Shams University Digestive System It consists of digestive tract and accessory organs. The digestive tract consists of Mouth Pharynx Esophagus Stomach Small intestine Large intestine The accessory...

Digestive System Dr. Noha Mohamed Gaber Lecturer of Anatomy & Embryology Ain Shams University Digestive System It consists of digestive tract and accessory organs. The digestive tract consists of Mouth Pharynx Esophagus Stomach Small intestine Large intestine The accessory organs are Salivary glands Liver Gall bladder Pancreas They secrete fluids containing essential enzymes for the digestion. Mouth Mouth cavity The vestibule: Is the space between the cheeks (or lips) and the teeth. Oral cavity proper: Palate Tounge Palate: Hard palate: Rigid surface against which food is forced in chewing Soft palate: Muscular structure that rises & blocks off the nasopharynx during swallowing Tongue: Muscular organ that grips & repositions food, mixes food with saliva & compresses food to form a food bolus, prior to swallowing. The Salivary Glands Supply most of the saliva via ducts ✓ Parotid gland: In front of the ear, Serous in secretion, drains in the vestibule of the mouth at the cheeks ✓ Submandibular gland: Below the mandible, Mucinous in secretion. ✓ Sublingual gland: Below the tongue, Mixed gland.  Parotid gland: Sublingual gland Submandibular gland Pharynx: oropharynx & laryngopharynx; muscular wall propels food to the esophagus Esophagus: Muscular tube (25cm) from laryngopharynx to stomach begins at (C6), passes through the diaphragm. Gastroesophageal(cardiac) sphincter: A physiologic sphincter that helps keep esophagus closed when empty Stomach The stomach is Most dilated part of GIT in the upper left part of abdomen. 2 Opening: Cardiac opening Pyloric opening and is guarded by the pyloric sphincter. Parts of stomach Cardiac region Fundus Body Pylorus then the Pyloric sphincter Borders of stomach: Lesser curvature Greater curvature Small Intestine: It consists of 3 parts: -Duodenum (25 cm) ”C shaped” -Jejunum (2.5 m). -Ileum (3.5 m), Ends at the ileocecal valve Both liver and pancreas open with the duodenum. The greatest amount of digestion and absorption occurs in the small intestine. The Large Intestine The large intestine extends from the ileocecal junction to the anus (Approx. 1.5m). It consists of: ✓ Cecum: blind pouch (below ileocecal valve) ✓ Appendix: attached to cecum (lymphoid) ✓ Colon: ascending, transverse, descending,sigmoid ✓ Rectum ✓ Anal canal Criteria of large intestine: Teniae coli: 3 ribbons of longitudinal smooth muscle Haustrations: pocket-like segments of large intestine Appendices epiploicae: fat filled pouches of visceral peritoneum Liver: It lies in the right upper quadrant of the abdomen against the inferior surface of the diaphragm. Anatomically it is divided into 4 lobes 1. Right lobe 2. Left lobe 3. Caudate lobe 4. Quadrate lobe Functions of the Liver: 1. Detoxification ( breakdown) of hormones, drugs, toxins. Conversion of poisonous ammonia to urea (urea is an end product of protein metabolism and is excreted in the urine 2. Storage: Glucose in the form of glycogen (glycogen can be converted back to glucose for energy) Vitamins and minerals ( Vit A, Vit B12, Iron and copper) 3. Synthesis: Bile (break down fats in the small intestine during digestion) Certain proteins for blood plasma Cholesterol and triglycerides Blood clotting factors Fights infections by making immune factors and removing bacteria from the bloodstream. Biliary System This system includes: 1- Gall bladder (3 parts; fundus, body & neck). The neck gives rise to cystic duct (3 cm) 2- Right & Left hepatic ducts unite forming Common hepatic duct (3 cm). 3- Bile duct opening (3 inches) formed by union of common hepatic & cystic ducts, which open in duodenum. Function: Storage of bile Pancreas ✓ It lies in the concavity of duodenum. ✓ It consists of head, neck, body and a tail which extends to the spleen. ✓ It has both Endocrine part secreting Insulin and Exocrine part secreting Digestive Juice.