Chapter 8

1. Chapter 8 Digestive System

2. Objectives • Identify the organs of the digestive system • Determine root words, prefixes and suffixes appropriate to this system • Identify portions of the tooth • Identify and define some common disorders • Identify and explain medical treatments and procedures pertaining to the digestive system

3. Gastroenterology • Branch of medicine specializing in the diagnosis and treatment of diseases, conditions, affecting the lower gastrointestinal tract. (GI tract) • Gastroenterologist is the physician who treats abnormal conditions of the GI tract

4. Digestive system • Also called the gastrointestinal system or • Alimentary system (Latin alimentum) means nourishment • Provides a tube like passage through a maze of organs and body cavities • Begins at the mouth • Ends at the anus

5. The three main functions: • Digestion • Absorption • Elimination

6. Digestion • Complex food material is taken in through the mouth and is digested (broken down) • Digestive enzymes speed up chemical reactions and aid in the break down of complex nutrients • Complex proteins are digested to amino acids

7. Digestion contd: • Complicated sugars are reduced to simple sugars such as glucose • Large fat molecules are broken down into fatty acids and triglycerides

8. Absorption: • Takes place when the digested food is absorbed into the blood stream • It is absorbed by going through the walls of the small intestine • Fatty acids and glycerol enter the lymphatic vessels mostly

9. Absorption contd: • By this method valuable nutrients such as sugar, fatty acids and amino acids, travel to all cells of the body • Cells then catabolize (burn) nutrients in the presence of oxygen to release energy stored within the food • Cells also use amino acid nutrients to anabolize (build) large protein molecules needed for growth and development

10. Elimination: • Third function is the elimination of solid waste material that cannot be absorbed into the blood stream. • The large intestine concentrates these solid wastes and pass it out of the body through the anus • The waste is commonly known as ‘feces’

11. Organs of the Digestive system • Mouth = or/o pertaining to the oral cavity • Also known as the buccal cavity • Includes the lips surround the opening to the cavity Cheeks: form the walls of the oval shaped cavity Hard palate: forms the anterior portion of the roof of the mouth Soft palate: muscular portion behind the hard palate. Made up of skeletal muscle and connective tissue

12. Mouth contd: • Rugae: Are irregular ridges in the mucous membrane covering the anterior portion of the hard palate • Uvula: small soft tissue projection , hangs from the soft palate. Aids in sound and speech • Tonsils: masses of lymphatic tissue located in depressions of the mucous membranes. They act as filters to protect the body from the invasion of microorganism

13. Mouth contd: • Tongue: solid, strong, flexible structure covered with mucous membranes. • It extends across the floor of the oral cavity, and muscles attach it to the lower jaw bone (mandible) • It moves food around during chewing (mastication) and swallowing (deglutition) • Principle organ for taste

14. Mouth contd: • Papillae: small raised areas on the tongue • Contain taste buds • Gums: Fleshy tissue that surround the sockets of the teeth

15. Teeth: • Every individual has two sets of teeth in their lifetime. The shape of the tooth determines its name • First set is ‘baby teeth’ (usually beginning to appear around age 6 months) are the primary teeth or deciduous teeth) and usually consist of 20 teeth. • Second set ‘permanent teeth’ (usually starting at age 6 years) consist of 32 teeth • Molar usually appear at age 17 years

16. Pharynx: • Also known as the throat • A muscular tube lined with mucous membranes • Food passes from the mouth to the pharynx to the esophagus • Passageway for air traveling from the nose to the windpipe

17. Esophagus: • 9 to 10 inch muscular tube from pharynx to stomach • Transports the food by means of peristalsis (involuntary process of wave like contractions)

18. Esophagus • the tube that connects your mouth and your stomach

19. Stomach: • Food passes from esophagus to stomach • Made up of the Fundus – upper potion, body- middle portion, and antrum- lower portion

20. Stomach contd: • Lining consists of folds called Rugae • This allows the stomach to stretch when food enters • Sphincters are rings of muscle that control the openings into and from the stomach • The cardiac sphincter relaxes and contracts moving food from the esophagus into the stomach

21. Stomach contd: • Pyloric sphincter allows food to leave the stomach when it has been broken down • Food is churned and mixed with gastric juices to make semi liquid called chyme • The stomach controls passage of food into the first part of the small intestine (duodenum) • Food leaves the stomach in 1 to 4 hours or more

22. Small intestine: • Also known as small bowel • Extends from the pyloric sphincter to the first part of the large intestine • It is about 21 feet long • Three parts; duodenum, jejunum, ileum. • Completes digestion by way of intestinal enzymes, pancreatic enzymes and bile from the liver

23. Large Intestine: • Extends from the end of the ileum to the anus • Four parts: cecum, colon, sigmoid colon, and rectum • About five feet long • Absorbs about 80% to 90% of fluids and electrolytes • Excretes waste and feces

24. Accessory Organs: • Salivary glands • Liver • Gallbladder • Pancreas

25. Salivary Glands: • Around the oral cavity there are three pairs of salivary glands. • Parotid gland, Submandibular gland, Sublingual gland • These glands produce saliva, which contain digestive enzymes • Narrow salivary ducts carry the saliva into the oral cavity

26. Liver: • Produces a thick greenish fluid called bile • Bile contains cholesterol, bile acids, and several bile pigments • Bile is continuously released from the liver • It then travels down the hepatic duct to the cystic duct which leads to the gallbladder which stores the bile

27. Liver contd: • Bile acts as an emulsifying agent on large fat globules • Without bile most of the fat in the body remains undigested • The liver also maintains normal blood glucose • Manufactures blood protein particularly the ones used for blood clotting • Remove poisons from the blood

28. Gall bladder: • Stores bile from the liver until needed in the duodenum to aid in digestion • We can do without our gallbladder • If removed bile will find another home in the biliary ducts to continue its process

29. Pancreas: • Both an exocrine and endocrine organ • As an exocrine gland it produces enzymes to digest starch, fat, and proteins • As an endocrine gland it secretes insulin, which is used as a carrier to bring glucose into cells of the body for energy

30. Root words: • An/o Anus • Appendic/o Appendix • Bil/I Gall, bile • Bucc/o Cheek (Facial) • Cec/o Belly • Cheio/o Saliva • Chol/e Gall, bile

31. Root Words contd: • Cholecyst/o Gall bladder • Col/o Colon/o Colon • Dent/o Teeth • Duoden/o Duodenum • Enter/o Small intestine • Esophag/o Esophagus

32. Root words contd: • Gastr/o Stomach • Gingiv/o Gums • Gluc/o Sugar • Glyc/o Sugar • Hepat/o Liver • Ile/o Ileum • Jejun/o Jejunum

33. Root words contd: • Labi/o Lips • Lingu/o Tongue • Gloss/o Tongue • Lip/o Fat, lipids • Or/o Mouth, oral • Pancreat/o Pancreas • Peritone/o Peritoneum

34. Root words contd: • Pharyng/o Pharynx • Proct/o Anus, rectum • Rect/o Rectum • Sigmoid/o Sigmoid colon • Splen/o Spleen

35. Prefix: • Re- Back • Retro- Backward, back

36. Suffix: • -ase Enzyme • -flux Flow • -iasis Abnormal condition • -lithiasis stone • -lytic destruction, breakdown • -pepsia digestion • -prandial meal

37. Suffix contd: • -orrhaphy suturing • -ostomy artificial opening • -tresia opening • -tripsy crushing