1. DIGESTION

2. Digestion Mechanical and chemical breakdown of foods...
Absorption of resulting nutrients by cells
ALIMENTARY CANAL: tube extending 9 meters from the mouth to the anus
Mucosa—Submucosa—Muscular layer- -Serosa
LUMEN: space within the intestines

3. Organs ALIMENTARY CANAL ACCESSORY ORGANS Salivary Mouth Glands Pharynx
Esophagus
Stomach
Small Intestine
Large Intestine
Anal Canal (rectum & anus)
Salivary
Glands
Liver
Gallbladder
Pancreas

4. Mouth Digestion begins here Mechanical & chemical (starches: amylase)
Lips, teeth, cheek, tongue, salivary glands, papillae, palate, frenulum, tonsils, vestibule, tongue

5. DIAGRAM OF MOUTH

6. Tongue
Function: Mix food particles with saliva during chewing and move food toward the pharynx during swallowing
PAPILLAE: bumps on tongue; taste buds
FRENULUM: flap that anchors tongue to bottom of oral cavity

7. Salivary Glands Moisten food; secret amylase to begin starch digestion
3 pairs of major salivary glands
PAROTID glands - largest of the major glands - secretes a clear, watery fluid rich in amylase
SUBMANDIBULAR glands - predominantly serous secretion w/ few mucous cells
SUBLINGUAL glands - smallest of the major glands - secretion primarily mucous type

8. DIAGRAM OF SALIVARY GLANDS

9. Teeth Function: Break pieces of food into smaller pieces
BOLUS: moist ball of food
INCISORS: (8) chisel-shaped with sharp edges to bite off larges pieces of food
CUSPIDS: (4) “canine” teeth; sharp
BICUSPIDS: (8) tear & grind
MOLARS: (12) flattened surface to grind food particles
<Wisdom Teeth> 3rd set of molars; late teens; early 20’s

10. Parts of Teeth CROWN: projects beyond the gum
ROOT: anchored to the alveolar process of the jaw
ENAMEL: covers the crown
DENTIN: bulk of the tooth below enamel
PULP: combination of blood vessels, nerves, and connective tissue (blood vessels and nerves reach pulp cavity through ROOT CANAL)
GINGIVA: gum

11. TEETH

12. TOOTH

13. Pharynx Connects the nasal & oral cavities with the larynx & esophagus
“back of throat”
3 parts
nasopharynx: communicates with the nasal cavity & provides a passageway for air during breathing
oropharynx: passageway for food moving downward from the mouth and for air
laryngopharynx: passageway to the esophagus

14. TONSILS Produce antibodies to fight infection TYPES LINGUAL PALATINE
PHARYNGEAL

15. Uvula Cone-shaped projection
Function: drawn upward during swallowing to close the opening between the nasal cavity & the pharynx

16. Esophagus passageway from the pharynx to the stomach “food tube”
25 cm long
PERISTALSIS: muscular contractions that move food
No digestion occurs here
EPIGLOTTIS: flap that closes trachea when we swallow to prevent food/liquid from entering the trachea
LOWER ESOPHAGEAL SPHINCTER: prevents food from backing up into esophagus

17. Stomach J-shaped pouch Just below diaphragm 1 L capacity or more!
RUGAE: folds
4 regions: cardiac, fundic, body, and pyloric
CHYME: semifluid paste of food
Chemical digestion of proteins
Gastric juice: HCl & pepsin…highly acidic (pH 2)
PYLORIC SPHINCTER - valve that controls food backing up in the stomach

18. FUNCTIONS OF THE STOMACH
Begins mixing process with gastric juice
Begins protein digestion
Moves food to small intestine
Limited absorption

19. THE STOMACH

20. Gastric Secretions
Gastric glands contain 3 types of secretory cells: mucous cells, chief cells, & parietal cells = gastric juices
Mucous cells secrete mucus to prevent stomach from digesting itself!
Chief cells secrete digestive enzymes
Parietal cells releases hydrochloric acid
Pepsin: digestive enzyme in gastric juice
Pepsin w/ HCl begins the digestion of nearly all proteins into polypeptide strands
Gastrin: hormone that regulates gastric secretions

21. Small Intestine Most important organ of digestion
6 m if stretched out!
Most absorption takes place here
Many folds (intestinal villi)– increase the surface area for easier absorption
3 regions: DUODENUM;
JEJUNUM;
ILEUM

22. Portions of Small Intestine
Duodenum
C shaped
Receives chyme from stomach
Receives pancreatic juice & bile
Several enzymes released to complete digestion of proteins, dipeptides, disaccharides, fats
Jejunum
Absorption of digested nutrients
Ileum

23. More about the Small Intestine
MESENTARY: tissue that suspends the jejunum & ileum from the abdominal wall
Lacteal: lymphatic capillary found in the intestinal villi
FUNCTIONS:
Receive secretions from pancreas & liver
Completes digestion
Absorbs products of digestion

24. Large Intestine Shaped like an upside down U 1.5 m long No villi
Absorbs water & electrolytes
Forms FECES (75% water; undigested material; bacteria; electrolytes
ILEOCECAL SPHINCTER: b/w ileum of small intestine & cecum of large intestine

25. Regions of Large Intestine
CECUM
ASCENDING COLON
TRANSVERSE COLON
DESCENDING COLON
SIGMOID COLON

26. Other Info to Know about the Large Intestine
APPENDIX: lymphatic tissue between small & large intestine
HEMORRHOIDS: “pain in the rear”…enlarged/inflammed rectal veins…itching, burning, bleeding
MUCUS produced in colon serves 2 functions:
Binds fecal matter
Protects intestinal wall against abrasive action of undigested waste
LARGE INTESTINE VS. SMALL INTESTINE: larger diameter
NO VILLI

27. Rectum & Anus Feces stored in the rectum
ANAL CANAL: passageway through which feces passes as it passes out the body through the anus
DEFECATION: removal of feces
INTERNAL & EXTERNAL ANAL SPHINCTERS control the release of feces

28. ACCESSORY ORGANS

29. Liver Heaviest organ is body (3 pounds)
Well-supplied with blood vessels
Right & left lobes
*blood sugar maintenance
*lipid metabolism (bile secretion)
Produce BILE
*emulsification of fats
*protein metabolism (most important function)
*stores glycogen, iron, vitamins A, B12, D
*removes toxic substances such as alcohol (detoxification)

30. Gallbladder Stores bile & releases bile to duodenum
Released through COMMON BILE DUCT
Cholesterol in bile can form crystals (GALLSTONES)

31. Pancreas Secretes pancreatic juice Enzymes that digest carbohydrates
(amylase), fats (lipases), proteins (trypsin…), & nucleic acids (nucleases)
Neutralizes stomach acid
Produces insulin
Pancreatic duct: connects with duodenum