1. DIGESTIVE SYSTEM
STRUCTURE

2. ALIMENTARY CANAL Digestive tract or GI (gastrointestinal) tract
30 ft. tube from mouth to anus
Consists of the mouth, throat, esophagus, stomach, small intestine, large intestine, and anus
See figure 18-1 pg. 377

3. ACCESSORY ORGANS of DIGESTION
Tongue
Teeth
Salivary glands
Pancreas
Liver
Gall bladder

4. PERITONEUM Lines abdominal cavity Serous membrane 2 layers: Mesentery
Attaches to posterior wall of abdominal cavity
Small intestines are attached to this layer
Greater omentum
Anterior portion of wall
Hangs over the organs like a “protective apron”
Contains large amounts of fat

5. MOUTH (FIGURE 18-2) Called the oral or buccal cavity
Covered in ________ membrane
Roof has hard and soft palates
Hard palate: formed from maxillary and palatine bones
Soft palate: behind hard, made from a movable mucous membrane fold and separates the mouth from the nasopharnyx
Uvula
Hangs from soft palate
Cone-shaped flap of tissue
Prevents food from entering the nasal cavity when swallowing

6. SALIVARY GLANDS Three pairs See figure 18-4
Parotid, submandibular, and sublingual
Parotid – largest
Found on both sides of the face, in front and below ears
Become inflamed when an individual has mumps
See figure 18-4

7. TEETH (FIGURE 18-5 and 18-6) Gingiva – gums
Support and protect the teeth
Deciduous (baby teeth) – 20
Start around 6 mons to 2 years and may last up to age 12
Adult mouth has 32 teeth
Start about age 6 to 25 years (wisdom)

8. ESOPHAGUS 10” long muscular tube Connects pharynx and stomach
Wall of esophagus has 4 layers
Mucosa, submucosa, muscular, and external serous layer
The muscles in the upper 3rd are voluntary and involuntary (smooth) on the lower part

9. STOMACH Cardiac sphincter Pyloric sphincter Rugae See figure 18-8
Opening from esophagus
Pyloric sphincter
Regulates entrance of food into the duodenum
Rugae
Folds in the gastric mucosa
See figure 18-8

10. SMALL INTESTINE Can be up to 20’ long Duodenum – 12” long
Curves around head of pancreas
Food comes from stomach
Gets digestive juices from pancreas and bile from liver
Jejunum – 8 ft. long
Ileum – 10 – 12 ft. long
See figure 18-9

11. PANCREAS Feather-shaped Located behind stomach
Endocrine and exocrine gland
See figure 8-12 pg. 388

12. LIVER Largest organ in body
Located below the diaphragm, upper right quadrant
Connected to gallbladder and small intestine by ducts
Figure 8-12

13. GALLBLADDER
Small, green organ
Inferior surface of liver
Figure 8-12

14. LARGE INTESTINE (Figure 18-13)
Colon
Approx 5’ long and 2” in diameter
Cecum
RLQ of abdomen
Blind pouch
Appendix
RLG below cecum
Fingerlike projection
No digestive function
Rectum
Opens to anus
7-8” long
Anus
Last portion of large intestine
Guarded by 2 sphincters
1 internal, 1 external