Digestive System Lecture (PDF)

7/6/2024 Objectives DIGESTIVE A) Describe...

7/6/2024 Objectives DIGESTIVE A) Describe parts of the Alimentary canal SYSTEM B) Describe the Accessory organs of digestion Dr. Rania Sherif Prof of Anatomy Mansoura Faculty of Medicine 1 2 Digestive system 1- MOUTH CAVITY A) Alimentary canal: is divided into two parts: This is a long tube through which food passes. 1- Vestibule: between cheeks & lips (externally) & teeth & gums (internally) It starts at the mouth and ends at the anus. It consists of the following parts: B) Digestive glands: 2- Mouth cavity proper: Enclosed by They are glands; their secretion pass through teeth ducts to enter the tract. Salivary glands Liver Pancreas 3 4 1  7/6/2024 2. Pharynx Parts of the pharynx: 1- Nasopharynx: ---- behind the nasal cavity. Definition: Wide muscular tube lined with mucous membrane. 2- Oropharynx: ---- behind the oral cavity. Extent: From the base of the skull to the level of the 6th cervical 3- Laryngopharynx: behind the larynx. vertebra where it becomes continuous Food pass into ????? with the oesophagus. 5 6 3. Esophagus Course & relation: Definition: Narrow muscular tube Begins in the neck. forming the food passage ( ) pharynx & stomach. Dimensions: Then Passes in the thorax. Length: 25 cm. Pierces the diaphragm & becomes continuous with the stomach. 7 8 2  7/6/2024 4. Stomach External features: 2 Ends: Cardiac (upper) end Definition: Most dilated part of the Pyloric (lower) end alimentary tract which connects the lower end of the esophagus to the Parts: duodenum. Fundus: above level of cardiac orifice Site: Lies obliquely in the upper & left part of the abdomen. Body: main part below fundus Shape: Variable, may be J-shaped Pyloric: lower narrow part, ended by pyloric sphincter 9 10 Parts of small intestine: 5. Small intestine A) Duodenum: - Shortest & widest part of the small Extent: From pylorus to intestine. ileocaecal junction. - Form C-shaped curve around the head of pancreas. Length: 6 meters long. - Length: 10 inches “25 cm”. Parts: B) Jejunum: - Middle part of small intestine. A) Duodenum. - Length: 2/5 B) Jejunum. C) Ileum: C) Ileum - Terminal part of small intestine. - Open into ceacum. - Length: 3/5 11 12 3  7/6/2024 6. Large intestine Length: 1.5 meters long. Parts: A) Caecum, B) Appendix. Accessory organs of C) Colon. Ascending colon. Transverse colon. Descending colon. digestive system Sigmoid colon. D) Rectum. E) Anal canal. 13 14 B) Digestive Glands 1. Salivary glands 1. Salivary glands Number: 3 pairs, Parotid Submandi Sublingual bular 2. Pancreas Side of the Below the Under the Site face mandible tongue 3. Liver Terminatio Vestibule Floor of Floor of n of its of the the mouth the mouth duct mouth 15 16 4  7/6/2024 2. Pancreas 3. Liver Site: Pale gray gland at the upper part of the abdominal cavity. Site: Largest gland in the Parts: body at the upper part of the - Head: Lies in the concavity of the duodenum. abdominal cavity on Rt side. - Body: Lies behind the stomach, in front of Lt kidney. Shape: Wedge-shape. It has 2 functions: Endocrine function: secretes insulin and glucagon Weigth: 1.5 K gm hormones which regulate the blood glucose level Exocrine function: secretes pancreatic enzymes which pass to the duodenum through the pancreatic duct. 17 18 Gall bladder It is located t the inferior surface Lobes: A) Large Rt lobe of the right lobe of liver B) Small Lt lobe It stores and concentrates bile. Then bile passes through its duct It has the following functions to reach the duodenum. Secretes bile (which is important for fat digestion). Synthesis of some substances (e.g.: albumin and clotting factors). Detoxifies several metabolites. 19 20 5  7/6/2024 21 6