1. The Digestive System: Anatomy
Digestion: breakdown of foods and the absorption of nutrients
Alimentary canal includes:
Mouth
Pharynx
Esophagus
Stomach
Small intestine
Large intestine
Rectum
Anus

2. The Digestive System: Anatomy
Walls of alimentary canal consists of:
Mucosa (carries out secretion and absorption)
Submucosa (carries away absorbed materials)
Muscular layer (provides movement of tube)
Serosa (protects underlying tissues)

3. The Digestive System: Anatomy
Accessory organs of alimentary canal include:
Teeth
Tongue
Salivary glands
Liver
Gallbladder
Pancreas

4. The Abdomen
Right upper quadrant (RUQ): liver, gallbladder, some of colon and small intestine
Left upper quadrant (LUQ): stomach, spleen, some of colon and small intestine
Right lower quadrant (RLQ): cecum, ascending colon, appendix
Left lower quadrant (LLQ): descending and sigmoid parts of colon

5. The Abdomen

6. Mouth Consists of lips, cheeks, gums, teeth, tongue
Lined by a mucous membrane
Roof is formed by hard and soft palates
Salivary glands produce nearly 1.5 L of saliva daily.
Saliva serves as a binder for chewed food and as a mouth lubricant.

7. Oropharynx
Tubular structure extending vertically from back of mouth to esophagus and trachea
Automatic movement of pharynx during swallowing
Moves liquids and solids into esophagus and away from trachea

8. Esophagus Collapsible tube about 10″ long
Extends from end of pharynx to stomach
Contractions of muscles in the esophagus wall propel food to the stomach.
Liquids pass with little assistance.

9. Stomach Hollow organ in left upper quadrant
Converts food to mixed, semisolid mass (chyme)
Moves chyme into small bowel in regular, small amounts

10. Pancreas Two intertwined portions:
Exocrine pancreas secretes pancreatic juice
Endocrine pancreas (islets of Langerhans) produces insulin
Insulin regulates the amount of glucose in blood.

11. Liver Largest solid organ in abdomen
Renders poisonous substances produced by digestion harmless
Forms factors necessary for blood clotting, plasma production, immune response
Produces bile to help digest fat
Stores sugar or starch for immediate use

12. Small Intestine Major hollow organ of abdomen
Absorbs more than 90% of products of digestion
Into veins to transport to liver
Components include:
Duodenum
Jejunum
Ileum

13. Large Intestine Components include:
Cecum
Colon
Rectum
Absorbs final 5% to 10% of digested food and water
Forms solid stool to pass out of body through anus

14. Appendix
3″ to 4″ long
Opens into cecum (first part of large intestine)
Easily becomes infected, producing appendicitis
One of major causes of severe abdominal distress

15. Rectum Lowermost end of colon Large, hollow organ
Stores quantities of feces until expelled
Anus is 2″ canal at end, lined with skin.
Sphincters (circular muscles) control the escape of liquids, gases, and solids.
Voluntarily and automatically

16. The Digestive System: Physiology
Functions of the digestive system:
Ingestion
Mechanical processing
Digestion
Secretion
Absorption
Excretion

17. The Digestive System: Physiology
In succession, different secretions (primarily enzymes) are added to food by:
Salivary glands
Stomach
Liver
Pancreas
Small intestine

18. The Digestive System: Physiology
Converts food into basic sugars, fatty acids, amino acids
These products cross wall of intestine and travel through portal vein to liver
Liver further processes and stores or transports to heart
Circulatory system then nourishes all cells