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

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)

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

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

The Abdomen

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.

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

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.

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

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

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

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

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

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

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

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

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

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