Digestive system

Digestive system

1. THE MOUTH:

   • is the first organ of the GI tract. The cheeks, hard and soft palates, lips, and tongue from the mouth. The vestibule is the space bounded externally by the cheeks and lips and internally by the teeth and gums.

2. Pharynx

   • is a funnel-shaped tube that extends from the internal nares to the esophagus posteriorly and to the larynx anteriorly, and it has both respiratory and digestive functions.

3. The esophagus

   • is a collapsible, muscular tube that connects the pharynx to the stomach. It contains an upper and lower esophageal sphincter.

4. The stomach

   • connects the esophagus to the duodenum (first part of the small intestine). The principal anatomic regions of the stomach are the cardia, fundus, body, and pylorus. Adaptations of the stomach for digestion include rugae; glands that produce mucus, hydrochloric acid, pepsin, gastric lipase, and intrinsic factor;

5. The small intestine

   • extends from the pyloric sphincter to the ileocecal valve. It is divided into a duodenum, jejunum, and ileum.

6. The large intestine

   • extends from the ileocecal sphincter to the anus. Its regions include the cecum, colon, rectum, and anal canal. The mucosa contains many goblet cells, and the muscularis consist of teniae coli and haustra.