1. The Digestive System

2. Functions Chemical and physical breakdown of nutrients
Elimination of solid waste
Absorption of nutrients into bloodstream

3. 2 Types of Digestion --Mechanical Digestion is physical.
Chew, tear, grind, mash, mix
Occurs in the mouth (teeth & tounge)
Occurs in stomach (churning and mixing)

4. 2 Types of Digestion Chemical Catabolic reactions Enzymatic hydrolysis
Carbohydrate- in mouth with salivase & intestines with carbohydrase
Protein- in stomach with protease
Lipid- in small intestines with bile

5. Digestion Phases Ingestion Movement Digestion Absorption
Further digestion

6. Terms to know
Alimentary canal – ft. long, runs from mouth to anus
Digestion – chemical breakdown of nutrients (begins in mouth, but mostly in stomach)
Ingestion – taking in of nutrients through the mouth
Absorption – passing of materials through alimentary wall to bloodstream
Defecation – release of solid waste through anus

7. Phases of Digestion

8. Digestive System Organization
Gastrointestinal (Gl) tract (Alimentary canal)
Tube within a tube
Structures
Mouth
Pharynx
Esophagus
Stomach
Small Intestine
Large Intestine
Rectum
Anus

9. Digestive System Organization
Accessory structures
Not in tube path
Organs
Teeth
Tongue
Salivary glands
Liver
Gall bladder
Pancreas

10. Anatomy of the Mouth and Throat

11. Human Deciduous and Permanent Teeth

12. Dorsal Surface of the Tongue

13. The Major Salivary Glands

14. Deglutition Deglutiton – act of swallowing
Peristalsis – wave-like contractions that move the nutrients
Uvula – bundle of nerves to alert throat that food is entering

15. Deglutition Pharnyx – common passageway for food and air.
Branches into trachea (air) and esophagus (food and liquid)
Epiglottis – flap that blocks either tube to prevent materials from going down the wrong tube. (If this doesn’t work you choke.)

16. Esophagus Features Usually collapsed (closed) Functions
Carry food and liquid to stomach through peristalsis
Features
Long, hollow muscular tube
Dimensions – 2cm by 25 cm

17. Peristalsis and Segmentation

18. Stomach chyme – slushy mixture – dissolved bolus Usually “J” shaped
Functions – most of chemical breakdown occurs here
Rugae – ridges on inside
allows for increased surface area and increased expansion
chyme – slushy mixture – dissolved bolus

19. Stomach
Four regions
Fundus – upper curve, stores excess bolus for digestion
Body – main part of stomach, where digestion occurs (makes bolus into chime)
Cardia – upper end, produces mucus to coat lining of stomach
Pyloric – last section before small intestine, where acidity in chyme is neutralized

20. Anatomy of the Stomach

21. Small Intestine Functions – absorption of nutrients into bloodstream
Regions
Duodenum
Jejenum
Ileum
Movements
Peristalsis

22. Small Intestine Dimensions – 6m by 4cm-25cm
Longest part of alimentary canal

23. Structure of the Villi in the Small Intestine

24. Small Intestine
Requires pancreatic enzymes & bile to complete digestion

25. Large Intestine
Function – reabsorption of water form chime and compaction of waste into feces (solid waste)

26. Large Intestine Regions
Rectum – storage of feces until release through anus
Cecum - appendix
Colon – has 3 regions, main part of large intestine
Ascending
Transverse
Descending
Anal canal

27. Anatomy of the Large Intestine

28. Feces Formation and Defecation
Chyme dehydrated to form feces
Feces composition
Water
Inorganic salts
Epithelial cells
Bacteria
Byproducts of digestion
Defecation
Peristalsis pushes feces into rectum
Rectal walls stretch
Control
Parasympathetic
Voluntary

29. Liver
Functions – blood cell formation, blood detoxification, bile (emulsifies fats) formation
Features – lobed, doesn’t grow much from birth to death
4 Lobes
Left
Quadrate
Caudate
Right
Each lobe has lobules – Contains hepatocytes – Surround sinusoids – Feed into central vein

30. Liver Detoxifies/removes Stores Activates vitamin D
Drugs
Alcohol
Stores
Gycolgen
Vitamins (A, D, E, K)
Fe and other minerals
Cholesterol
Activates vitamin D
Metabolizes absorbed food molecules

31. The Duodenum and Related Organs

32. Gallbladder Functions – storage of bile
Features – small, pear-shaped organ; found in lobes of liver; muscular

33. Appendix
Functions – may have been a 2nd stomach; new research shows it may make digestive enzymes produced no where else in the body
Features – 7-9 cm (varies); redish, worm-like sac; open only at one end; attached to cecum

34. The Organs and Positions in the Abdominal Cavity

35. Structures of the Alimentary Canal

36. Crohn’s Disease

37. Acid Reflux Stomach acid flows backwards causing irritation.
Symptoms – burning pain in the chest after eating or lying down

38. Gastritis
Inflammation of the stomach lining due to infection, injury, regular use of NSAIDs, too much alcohol
Symptoms - upper stomach pain, nausea, vomiting

39. Ulcers
A sore on the lining of the esophagus, stomach, or small intestine
Caused by damage due to stomach acid
Symptoms – upper abdominal pain

40. Diverticulitis
Inflammation or infection of the pouches of the intestine
More common after 40
Symptoms – abdominal pain, fever, nausea, change in bowel movements

41. Gastric Bypass surgery