Be sure to refresh your memory on the anatomy and physiology of the GI tract and its accessory organs. You may omit the Oral Cavity from your review. The entire GI tract is described as a regionally specialized tube with each region being specialized to carry out one or more of the above processes of digestion. For example, the mouth is specialized for mechanical degradation by chewing, for liquification by salivary secretions, and for limited enzymatic hydrolysis via salivary amylases. Since absorbed nutrients enter hepatic portal circulation and require a sequential passage of materials through the specialized regions of the GI tract, interference with either of these activities can have both GI and cardiovascular repercussions.
Liver damage can impair lipid digestion and cause cardiovascular portal hypertension.
So, as you work through the lecture material, think of potential impact on related organ systems. As you read through the lecture, look up each of the topics highlighted in blue in your textbook to broaden your knowledge in each of these areas. The esophagus is a muscular tube connecting the laryngopharynx and the stomach cardia. The muscular component of the esophagus consists of two smooth muscle layers within the wall, one with longitudinally oriented fibers and another with circular fibers. Coordinated contractions of these two muscle layers produce peristaltic waves that move food material toward the stomach.