1. The Digestive System

3. Salivary Glands
Saliva: cleanses, dissolves food, moistens food (bolus), contains enzymes for starch breakdown (amylase)
Slightly acidic pH

4. Palate Forms roof of the mouth Hard palate: rigid (palatine bones)
Soft palate: skeletal muscle
Uvula: closes off nasopharynx when we swallow

5. Tongue Skeletal muscle fibers Grips food when chewing Mixes food
Filiform papillae: friction
Fungiform and circumvallate papillae: tastebuds

6. Teeth -Lie in sockets (alveoli) -Mastication: chewing
-Each tooth has a crown (exposed) and gingiva or gum (surrounds tooth)
-Enamel: bears the force of chewing
-Root: embedded
-Dentin: bonelike-forms bulk of tooth
-Deciduous teeth: baby teeth (milk)
-Permanent teeth: 32 in a full set
Gingivitis: tartar build up inflames gums
Teeth

8. Alimentary canal (GI tract)
Digests food
Absorbs
About 30 feet long

9. Digestive Process Ingestion Propulsion 1. swallowing 2. peristalsis
Mechanical Digestion
1. chewing
2. mixing food with tongue
3. churning in stomach
4. segmentation (rhythmic local constriction of
intestines (mixes food and increases absorption)

10. Digestion continues… Chemical digestion (enzymes)
Absorption (small intestine)
Defecation (elimination of indigestible substances via the anus)

11. Peritoneum Serous membrane
Visceral peritoneum covers external surfaces of digestive organs
Parietal peritoneum lines the body wall
Serous fluid lubricates
Mesentery is a double layer of the peritoneum-provides blood vessels, nerves, lymphatics, and holds organs together

12. Pharynx
From mouth food passes through the oropharynx and then laryngopharynx (common passageways for food, fluids, and air)
Mucosa covered skeletal muscle
Bolus: ball of moistened food

13. Esophagus
Food tube
Collapsed when not involved with food propulsion

14. Stomach Temporary food storage tank Protein breakdown begins here
Chyme: creamy food paste
Rugae: longitudinal folds
Gastric glands (parietal cells) secret HCl
Chief cells produce pepsinogen-the presence of HCL helps convert it to pepsin to digest proteins
Fundus
Lesser
curvature
Greater
curvature
Body

16. Small Intestine Anatomy

17. Small Intestine Major digestive organ Digestion is completed here
All absorption of nutrients occurs here
3 subdivisions:
1. duodenum: bile and pancreatic ducts
about 10 inches long
2. jejunum: 8 feet long
3. ileum: 12 feet long
Joins the large intestine at the ileocecal valve
Villi and microvilli: increase surface area for absorption
Pancreatic juices and bile from liver break down all classes of food

18. Liver Largest gland in the body 4 lobes
Produces bile (bile salts and bilirubin-pigment) for lipid (emulsifies fat into a solution) digestion
Liver
Hepatitis: inflammation due to infection
Cirrhosis: chronic inflammation of liver usually due to
Toxins like alcohol and drugs –becomes fatty scar tissue

19. Gall Bladder Thin walled, green muscular sac Stores bile
Found on the undersurface of the liver

20. Pancreas Accessory digestive gland
Pancreatic juices breakdown all categories of foodstuffs (delivered to the duodenum)

21. Large Intestine Frames small intestine 6 meters
Absorbs water from indigestible food residues
Malabsorption: celiac disease - gluten
Eliminates them from the body as semisolid feces
Bacterial flora: help break down carbs and release gas – also synthesize B complex and K vitamins (clotting factor)
Subdivisions:
1. cecum (appendix located here)
2. colon: ascending, transverse, descending
3. rectum: stores feces
4. anal canal: removal of feces

23. Piggy Guts