1. The DIGESTIVE System

2. Digestion defined Breakdown of food into useable nutrients Two kinds
Mechanical
Chemical

3. Chemical Vs Mechanical Digestion
Chemical: Enzymes break down for absorption--ENZYMES
Mechanical: broken down into smaller parts--MASTICATION AND MACERATION

4. Alimentary canal Tube food passes through
Begins at mouth - ends with anus
Food is chewed
Bolus created
Bolus swallowed

5. Pharynx Bolus moves into pharynx fancy word for throat has three parts
Nasopharynx
Oropharynx
Laryngopharynx

6. Esophagus 8-12 inches long Smooth muscle contractions called:
Peristalsis-rhythmic
Cardiac (aka Gastroesophageal) sphincter
Has no mucous membrane to protect from Hcl from stomach

7. Stomach J-shaped 3 sets of muscle in different directions
Hcl= chemical breakdown
Pepsin begins protein disgestion
Contain rugae to increase surface area
Change bolus into chyme
Mucus protects stomach lining

8. Small intestine
3 parts
Duodenum--most chemical digestion takes place here
Jejunum-absorption continues
Ileum absorption continues
15-22 ft long
Absorbs some of the water in food & what you drink

9. Villi
Nutrients are absorbed through structures called villi

10. Large intestine called the colon
Main function water absorption + Vit K absorption
Begins with cecum-contains lymphatic organ called appendix
Ascending colon

11. Large intestine Ascending colon Transverse colon-makes hunger sounds
Descending colon
Sigmoid colon
Rectum
Anal canal
Anus

12. Accessory organs CONTRIBUTE to digestion process
NOT part of the canal or tube
Food DOES NOT pass through them

13. Tongue and teeth Teeth break food down into smaller pieces
Tongue moves food to the back of throat

14. Parts of a tooth Crown = exposed portion above gum line
Neck = between crown & root
Gingivae-gums
Root = one to three-- embedded in mandible & maxillae

15. Parts of a tooth Enamel = outermost part, protects from wear & tear
the hardest substance in the body
Dentin = calcified connective tissue
Gives tooth it’s basic shape & rigidity

16. Parts of a tooth
Pulp Cavity = large cavity enclosed by dentin--filled with pulp
Cementum = a bone-like substance covers--dentin of roots

17. Parts of a tooth Periodontal Ligament
an area of dense fibrous connective tissue
anchors teeth in position
serves as a shock absorber when chewing

18. Salivary glands Saliva is: Mostly water
Enzymes that digest carbs—Amylase—breaks starch into maltose
Soften and moisten food

19. Salivary glands
6 total--3 pair
Parotid, submandibular, and sublingual

20. Liver and Gall Bladder Liver makes bile
Bile is stored in gall bladder (sac)
Bile breaks down fats--emulsification
Secreted as it is needed
Eliminated through intestines

21. Pancreas Located posterior to stomach
Secretes enzymes to chemically breakdown fats, carbs, and proteins
Increases pH of chyme
Pancreatic juice—thru pancreatic duct—thru heptopancreatic sphincter

22. Mastication Chewing--makes bolus Teeth mechanically break down food
Food is mixed with saliva

23. Deglutition Swallowing Tongue pushes food to back of throat
Oropharynx--second part of throat
Smooth Muscles contract causing peristalsis
Voluntary

24. Peristalsis
General term for wave-like contractions in esophagus and intestines
Rhythmic smooth muscle contractions

25. Maceration
Stomach contracts and Bolus mixed with gastric juices and Hcl until it is liquid-like
Bolus is changed to chyme
Empties through pyloric sphincter

26. Segmental contraction
Each segment of small intestine contracts
Helps mix bile and pancreatic juices with chyme
Smooth Muscle contractions peristalsis in each segment

27. Absorption Nutrients absorbed in jejunum and illeum
Some nutrients & water absorbed thru stomach
Some water absorbed through small intestine
Most water absorbed through large intestine

28. Haustral churning Each segment in large intestine is called a haustra
Smooth muscle contractions move contents along (type of peristalsis)
Water is absorbed in large intestine

29. Defecation Elimination of material that is undigestible
Plant fiber--necessary for health of the intestines
Formation of feces and elimination of feces

30. Nutrients are broken down in different places in digestive system
Carbohydrates
Begin digestion in mouth with enzyme AMYLASE from salivary glands
Amylase breakdown continues in stomach
Finish breakdown in duodenum (pancreatic juice)

31. Fats Fats begin mixing with gastric juices in stomach
Bile from gall bladder goes into small intestine to break them down
Pancreas secretes enzymes (lipase) to finish chemical breakdown

32. Proteins Begin mixing with pepsin in stomach
Finish with secretions from pancreas into duodenum

33. Digestion system End