As you explore the pathways taken by food and air keep in mind the relationship between the structures that make up the pathways.

Click here to see the relationship between the various cavities shown above.

From the glottis air passes into the larynx and continues toward the lungs in the trachea. The lungs are where gas exchange occurs. Food follows a parallel path in the esophagus. The body wall and epithelial tissue have been reflected to show the position occupied by the lungs and the heart. The lungs appear blue in this photo because they are filled with blue latex that was injected to highlight the venous portion of the circulatory system. The diaphragm forms the posterior margin of the thoracic cavity.

Click to examine the membranes that cover the organs in the thoracic cavity.

Click here to explore the glands associated with the facial region.

Click to follow the pathway taken by food through the diaphragm and into the abdominal cavity.

Food passes through the thoracic cavity enclosed in the esophagus and enters the stomach (1), which is located ventral to the liver in the abdominal cavity. In the image on the left the liver has been reflected toward the diaphragm to make it easier to see the digestive organs. Trace the food from the stomach (1) through the digestive organs. The first portion of the small intestine is the duodenum (2) followed by the jejunum (3), and ileum (4). The ileum connects to an enlarged pouch, the caecum . Food then proceeds into the colon with the ascending (5), transverse (6) and descending (7) regions before entering the rectum and passing out of the body through the anus.

Click to reflect the abdominal organs to the right to view the relationship between several organs and mesenteries that lie in the abdominal cavity.

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