1. Digestive System- Anatomy

2. Alimentary canal- open tract of major organs through which food travels
Mouth
Pharynx
Esophagus
Stomach
Small intestine
Large intestine
Anal canal

3. Accessory organs- organs that aide in digestion process
Salivary glands
Tongue
Teeth
Liver
Gallbladder
Pancreas
Vermiform appendix

4. Mouth/Oral Cavity- beginning of alimentary canal
3 major pairs salivary glands- secrete 1 liter of saliva per day
Parotid: largest
Submandibular: Wharton ducts beside frenulum
Sublingual: below floor of mouth
Secrete mucous/serous saliva to aid in digestion

5. Teeth
Used for mastication/chewing– increases surface area of food for more enzyme access
Deciduous= baby teeth-20
Permanent= adult – 32
Incisors- bite into food
Canines/cuspids -tear
Premolars- grind & crush
Molars- grind & crush

6. 3 Main Parts of Tooth 1. crown- exposed top covered with
enamel= 97% calcified material
dentin= softer, more elastic than enamel, yellow
2. neck- narrow, surrounded by gums and cementum
3. root- fits into jaw, anchors tooth, surrounded by cementum

7. Interior of tooth= pulp cavity
Contains: connective tissue, blood, lymph, nerves

8. Swallowing
After food leaves mouth it’s called a bolus- goes through pharynx
Pharynx=throat
Oropharynx= 2nd division of pharynx through which food is passed  connects to esophagus

9. GI tract- layers of gastrointestinal tract
1. Mucosa- mucous lining the interior
2. Submucosa- CT tissue with blood vessels

10. Layers of GI 3. Muscularis- muscle with plexus of nerves
4. Serosa- fibroserous layer, includes mesentery (later in GI)

11. Esophagus

12. Esophagus- beginning of GI proper
10 inches long- takes about 7 seconds for food to pass through to stomach
Normally flat at rest—expands during peristalsis
Lined with stratified squamous epithelium– resists abrasion

13. Stomach Fundus– goes above level of esophagus Body Pylorus
Volume about liters– large size after big meal interferes with diaphragm– located to left side
3 major divisions:
Fundus– goes above level of esophagus
Body
Pylorus

14. Stomach
Destroys most bacteria swallowed in food or with mucus from resp. tract
Stores food, churns food
Limited amount of absorption– some drugs, alcohol, some fats

15. Gastric Mucosa Lining with folds= rugae, and depressions= gastric pits
Gastric glands below pits– secrete gastric juice
Have 2 main secretory cells:
1. chief cells- secrete enzymes
2. parietal cells- secrete HCl and “intrinsic factor”– binds to vitamin B1 to protect it from HCl before intestine, aids in absorption

16. Gastric Muscle
3 layers of smooth muscle running at different angles--longitudinal, circular, oblique-- so it can contract multiple directions

17. Small intestine Villi located on folds called plicae
Each villi has arteriole, venule, and lymph vessel and have “brush border”– microvilli on columnar epithelium
Crypts- depressions where mitosis is rapid

18. Parts of Large intestine
Cecum- 1st few cm—pouch which appendix attaches to
Ascending colon- goes up right side where ileum attaches- ileocecal valve allows material in (1 way)
Transverse-horizontal
Descending-goes down left side
Sigmoid- S curve, joins rectum
Rectum- last few inches