1. Digestive System (Consists of alimentary canal and accessory organs)
Functions of the Digestive system:
Intake and digestion of food
Absorption of nutrients from digested food
Elimination of solid waste material
Gastrointestinal (gastr/o + intestin/o = -al)
Accessory Organs of Digestion:
Include the liver, gallbladder, and pancreas

2. Anatomy Structures are divided into two sections:
Upper GI tract – mouth, esophagus, stomach
Lower GI tract – small intestine, large
intestine, rectum, anus
Oral Cavity (mouth)
Lips – form opening to the mouth
Hard palate – anterior portion of roof of mouth
Soft palate – posterior portion of roof of mouth, closes off nasal passage during swallowing
Uvula – helps in producing sound and speech

3. Upper GI tract Cont’d.
Tongue – strong and flexible, aids in speech and moves food during chewing and swallowing, contains papillae which are also known as taste buds.
Teeth – 20 baby teeth, 32 permanent teeth; four kinds:
Incisors
Canines
Premolars (bicuspids)
Molars

4. Upper GI tract Cont’d.
Gingiva (gums) – surrounds teeth, covers the bone of the dental arches, forms the lining of cheeks
Salivary Glands – secretes saliva to moisten food, begins digestive process, cleanses the mouth
Mastication – also known as chewing, it breaks down food into smaller pieces

5. Upper GI tract Cont’d. Pharynx (also known as the throat)
common passageway for food and air
During swallowing, food is prevented from moving
from the pharynx into the lungs by the epiglottis.
Esophagus
collapsible tube that leads from the
pharynx to the stomach

6. Upper GI tract Cont’d. Stomach
has 3 sections: fundus, body, and the antrum
gastric juices begin to breakdown food (Chyme)
the pyloric sphincter controls flow from stomach into the duodenum of the small intestine.
Peristalsis - series of wavelike movement of smooth muscles in a single direction.
Chyme – semi-fluid material of partially digested food that passes from stomach into small intestine.

7. Lower GI tract
Small Intestine – extends from pyloric sphincter to the large intestine; in the small intestine is where nutrients are absorbed into bloodstream; 20 feet in length; has three sections:
Duodenum – first section, closest to the stomach
Jejunum – middle section, between duodenum and ileum
Ileum – last section, closest to the large intestine

8. Lower GI tract Cont’d.
Large Intestine – waste products of digestion are processed in the large intestine and excreted through the anus; has 6 sections :
Cecum – pouch that pouch that extends from the ileum to the beginning of the colon
Ascending colon – travels upward from cecum
Transverse colon – passes right to left toward the spleen
Descending colon – travels down
the left side of abdominal cavity
Sigmoid colon – joins descending
colon with the rectum
Rectum – last part of the large intestine
Anus – solid waste is passed out of the body through the anus
Defecation – evacuation or emptying of the large intestine.

9. Accessory Organs of Digestion
Liver (located in the right upper quadrant)
removes excess glucose from the bloodstream
destroys old red blood cells
removes poisons from blood
makes some blood proteins
secretes bile to break down fat
Gallbladder (cholecyst/o)=gal, bile, bladder
stores and concentrates bile for later use
Pancreas
located posterior to the stomach, creates pancreatic juices to neutralize stomach acids and digestive enzymes to process protein, carbohydrates, and fat.

10. Flow through the Digestive System
You will need to know the order of flow for food moving through the digestive system.
The Language of Medicine, 7th Edition; Chabner, Davi-Ellen; Saunders, 2004