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