1. The Digestive System

2. The Digestive System: Function
Preparation of food for absorption and use by the millions of body cells
Alimentary canal - tube through your body that performs the above function.

3. The Mouth Structure Lips: outer boundary
Cheeks: mucous membrane lateral boundary
Hard/soft palate - uvula extends from
Tongue

4. Tongue Places food during chewing Papillae contain taste buds
Multiple blood vessels under tongue = high absorption of soluble drugs into circulation
Ex. Nitroglycerin pills for heart attack,
Vitamins

5. Salivary Glands Parotid = largest Submandibular Sublingual = smallest
Located in front of and below ear
Produces watery substance with enzymes
Submandibular
Located below mandibular angle
Produces enzymes and mucus
Sublingual = smallest
Under floor of mouth
Produces mucous type of saliva

6. Salivary Glands: Function
Begins the break down of food through hydrolysis.
Carbohydrate digestion begins in the mouth with aid of saliva.

7. Teeth Crown - exposed covered with enamel
Neck - surrounded by gums (gingiva)
Root - fits into socket

8. Teeth Coverings Enamel - Hardest substance in body
Dentin - tissues, nerves, blood vessels
Cementum - covers dentin

9. Dentition Deciduous Teeth 20 total Baby teeth Primary teeth 8 incisors
4 cuspids
8 molars

10. Dentition Permanent Teeth 32 Total
Adult teeth
Secondary teeth
32 Total
3rd set of molars come in after age 17 (wisdom teeth)

11. Other Organ Components
Pharynx
Receives bolus (rounded mass of food)
Carries bolus to esophagus
Esophagus
Collapsible tube that enters the stomach
Posterior to trachea and heart
Protected by a thick layer of mucus

12. Esophagus Continued
Food (Bolus) moves through the esophagus and the rest of the alimentary canal by peristalsis - involuntary muscle contractions.

13. Stomach Located below diaphragm and liver
Enlarges after meals then collapses
Size of large sausage

14. Stomach Divisions Fundus - large portion at end of esophagus
Body - central portion
Pylorus - lower portion near small intestine

15. Sphincter Muscles Guard openings to stomach
Cardiac - esophagus to stomach
Pyloric - lower portion of stomach to small intestine.
Pylorospasm - muscle will not relax to allow passage of bolus = vomiting

16. Stomach Function Food storage Secretion of gastric juices
Churning of food and breakdown into chyme - liquid food.
Absorption = water, alcohol, and drugs
Glands of stomach
Gastric - secret gastric juice
Mucus - contains enzymes and hydrochloric acid.

17. Small Intestines 20 feet long Divisions
Duodenum = uppermost area, attaches to stomach.
Jejunum = middle area
Ileum = end portion, leads to large intestine.
All set in place by mesentery (membrane)

18. Small Intestines Continued
This is where most digestion occurs.
Absorption of digestive products.
Inside surface of small intestines covered with tiny projections called villi.
1mm projections
Increase surface area by 160x

19. Large Intestines 5-6 feet long Divisions
Ascending colon - right side of abdomen
Transverse colon - horizontally across abdomen and under liver
Descending colon - left side of abdomen
Rectum - last 7-8 inches
Anus - contains many arteries and veins
Hemorrhoids - enlargement of veins in anal canal.

20. Large Intestines Continued
Water/electrolyte absorption
Forms/stores feces

21. Large Intestines Continued
Appendix
Located just behind cecum
No functional importance in digestion.
Appendicitis = inflammation of the appendix

22. Accessory Organs Liver structure Liver function Largest gland in body
Under diaphragm
Able to regenerate
Liver function
Detoxifies many substances
Makes and secretes bile
Metabolizes proteins, fats, and carbs

23. Accessory Organs Gall bladder Stores bile, increases its concentration
Bile breaks down fat.
During digestion, empties bile into small intestines

24. Accessory Organs Pancreas Secretes digestive enzymes Secretes insulin
Secretes glucagon (raises blood glucose levels)