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Digestive Organs. Overview Digestive System Overview Digestive System Alimentary Canal (Gastrointestinal Tract) The continuous tube that carries food.

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Presentation on theme: "Digestive Organs. Overview Digestive System Overview Digestive System Alimentary Canal (Gastrointestinal Tract) The continuous tube that carries food."— Presentation transcript:

1 Digestive Organs

2 Overview Digestive System

3 Overview Digestive System Alimentary Canal (Gastrointestinal Tract) The continuous tube that carries food from the mouth to the anus.

4 Overview Digestive System Alimentary Canal (Gastrointestinal Tract) The continuous tube that carries food from the mouth to the anus. Accessory Digestive Organs Organs that contribute to the digestion of food even though food does not pass directly through these organs.

5 Overview Digestive Processes

6 Overview Digestive Processes Mechanical Digestion: The physical breakdown of food. Ex: Grinding of the teeth or churning of the stomach.

7 Overview Digestive Processes Mechanical Digestion: The physical breakdown of food. Ex: Grinding of the teeth or churning of the stomach. Chemical Digestion: The catabolic breakdown of food using enzymes and acids.

8 Overview Digestive Processes Mechanical Digestion: The physical breakdown of food. Ex: Grinding of the teeth or churning of the stomach. Chemical Digestion: The catabolic breakdown of food using enzymes and acids. Absorption: The passage of digested food from the lumen of the GI Tract into the blood or lymph.

9 Structures and Functions of the Digestive System

10 Mouth

11 Tongue: Mixes food.

12 Mouth

13 Teeth: Tear and grind food.

14 Mouth Teeth: Tear and grind food. Layers Enamel Dentin Pulp

15 Mouth Teeth: Tear and grind food. Types

16 Mouth Teeth: Tear and grind food. Types Incisors - chisel-shaped - cutting

17 Mouth Teeth: Tear and grind food. Types Canines - eye-teeth - tearing

18 Mouth Teeth: Tear and grind food. Types Premolars Molars - Broad crowns - grinding

19 Mouth Salivary Glands: Moisten food and contain enzymes for the breakdown of starchy foods.

20 Salivary Glands Three pairs of major salivary glands (parotid, submandibular, and sublingual glands) and numerous smaller ones secrete saliva into the oral cavity, where it is mixed with food during mastication. Saliva contains water, mucus, and enzyme amylase. Functions of saliva include the following: It has a cleansing action on the teeth. It moistens and lubricates food during mastication and swallowing. It dissolves certain molecules so that food can be tasted. It begins the chemical digestion of starches through the action of amylase, which breaks down polysaccharides into disaccharides

21 Pharynx Common passageway for food and air. Pharynx

22 Esophagus Propels food to the stomach via peristalsis. Esophagus

23 Stomach Storage of food and digestion of protein. Stomach

24 Stomach (in detail) Curvatures Greater Curvature Lesser Curvature

25 Stomach (in detail) Sphincters Gastroesophageal Sphincter Pyloric Sphincter

26 Stomach (in detail) Regions Fundus Body Pyloric Antrum

27 Stomach (in detail) Rugae Rugae: Large, longitudinal folds of the mucosa

28 Small Intestine Majority of digestion and absorption occurs here.

29 Small Intestine - Sections Duodenum First 10 inches of the small intestine. Collects bile from the liver. Collects pancreatic juices from the pancreas. Sphincter of Oddi controls entry of the bile and juices.

30 Small Intestine - Sections Jejunum - Next 8 feet. Ileum - Final 12 feet. Ileocecal Valve - The small intestine joins the cecum of the large intestine.

31 Large Intestine Large Intestine (Colon) Absorbs water and some nutrients.

32 Large Intestine - Sections 1. Cecum 2. Ascending Colon 3. Transverse Colon 4. Descending Colon 5. Sigmoid Colon 6. Rectum 7. Anus

33 Large Intestine - cont. Taniae coli: Smooth muscle that causes the colon to pucker. Haustra: Pocket-like sacs. Appendix: Contains lymphoid tissue that aids the immune system.

34 Accessory Organs of Digestion Liver: Produces bile to aid in the digestion of lipids.

35 Accessory Organs of Digestion Gallbladder: Stores bile until it is released into the small intestine.

36 The liver is stimulated by the hormones secretin and cholecystokinin (CCK) to produce bile. The bile enters the right and left hepatic ducts and travels to the common hepatic duct. The bile is stored in the gallbladder. The gallbladder is stimulated to release the bile by the vagal nerve and CCK. The bile enters the duodenum via the bile duct. Bile Secretion in Detail Common hepatic duct Right and left hepatic ducts Gallbladder Bile duct Duodenum

37 Accessory Organs of Digestion Pancreas: Produces many types of enzymes used in the small intestine to digest food.

38 Pancreatic Juice Secretion in Detail Pancreas Duodenum Main pancreatic duct The hormones cholecystokinin and secretin stimulate the release of pancreatic juices by the pancreas. The juices travel through the pancreatic ducts to enter the duodenum.

39 Control of Digestion - Nervous System Two Phases: Cephalic Phase - Triggered by the site, smell, and taste of food. This stimulates the stomach to prepare for the entry of food.

40 Control of Digestion - Nervous System Two Phases: Cephalic Phase - Triggered by the site, smell, and taste of food. This stimulates the stomach to prepare for the entry of food. Gastric Phase - Stomach distension by food stimulates the release of gastric juices.

41 Control of Digestion - Hormones Gastrin - Produced by the stomach; stimulates the release of gastric juices.

42 Control of Digestion - Hormones Gastrin - Produced by the stomach; stimulates the release of gastric juices. Secretin - Produced by the small intestine; stimulates the pancreas and gall bladder to release pancreatic juices and bile.

43 Control of Digestion - Hormones Gastrin - Produced by the stomach; stimulates the release of gastric juices. Secretin - Produced by the small intestine; stimulates the pancreas and gall bladder to release pancreatic juices and bile. Cholecystokinin (CCK) - Produced by the small intestine; stimulates the pancreas and gall bladder to release pancreatic juices and bile.

44 Digestive Tract

45 Digestive Disorders Peptic Ulcer Lesions in the wall of the stomach or duodenum. Primarily caused by bacteria. Treated with antacids AND antibiotics.

46 Digestive Disorders Appendicitis Usually caused by fecal obstruction or anatomical kinking of the appendix. A rupture leads to peritonitis (ouch)

47 Digestive Disorders Peritonitis (Inflammation of the Peritoneum) Usually results from an infection caused by a external or internal penetrating wound. Bacteria from intestines enter the sterile areas of the body surrounding the digestive system. May cause death if not treated with high doses of antibiotics.

48

49 Digestive Disorders Hepatitis (Inflammation of the liver) Caused by drugs, chemicals, viruses, alcohol, etc. Viral Hepatitis A is usually caused by the ingestion of food. Viral Hepatitis B and Hepatitis C are blood-borne pathogens.

50 Digestive Disorders Diverticulitis Small bulges (herniations) of the mucosa in The large intestine. These areas can become inflamed and possibly rupture. Prevention is the treatment of choice. A diet high in fiber will help prevent diverticulitis.

51 Diverticulitis

52 Digestive Disorders Emesis (Vomiting) Can be caused by microbes, allergies, gluttony, poisons, etc.

53 Digestive Disorders Diarrhea Movement of fecal material through the GI Tract too rapidly. May be caused by microbes, spicy foods, stress, etc.

54 Digestive Disorders Constipation Infrequent defecation of fecal material. Usually caused by a diet low in fiber and water.

55 Digestive Disorders Cirrhosis of the Liver Condition where liver cells are destroyed and replaced by fibrous connective tissue. Alcoholism is a common cause of cirrhosis.

56 Digestive Disorders Gall Stones (Biliary Calculi) Crystalization of cholesterol and bile salts. Blocks the bile duct or fills the gall bladder.

57 Gallstones: MRI showing transverse section of abdomen

58 Digestive Disorders Jaundice Build-up of bile in the skin causing a yellowing of the skin. May be caused by damage to the liver, gall bladder, or any of the ducts that service these organs.

59 Jaundice

60 Digestive Disorders Buliemia Nervosa Condition where a patient binges on food and then purges with either laxatives or vomiting. Considered a psychological disorder where the patient has a fear of gaining weight. Treated with psychotherapy.

61 Digestive Disorders Anorexia Nervosa Psychological disorder where the patient has a false perception of their own weight. Patient denies their own appetite. Patients are usually % below normal body weight. Extreme cases are lethal. Closely associated with bulimia nervosa.

62 False perception of my weight. It can affect men and women It should never be considered fashionable

63 Digestive Disorders Flatulence Excessive intestinal gas resulting from bacteria in the intestines, diet, or swallowing air.


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