The stomach is located on the left side of the body, just inferior to the diaphragm. It is the part of the alimentary canal located between the esophagus and the small intestine. The stomach has an upper cardia and a small domed portion called the fundus. The stomach contents are restricted from flowing back into the esophagus by the esophageal sphincter. If stomach fluid refluxes into the esophagus, it is felt as "heartburn."
The main portion of the stomach is the body and the narrow region, leading to the duodenum is the antrum or pyloric region. This leads to the pyloric canal which is controlled by the pyloric sphincter. The greater curvature is located on the left edge of the stomach and the lesser curvature is on the right side. The stomach has inner ridges called rugae which allow for expansion of the stomach.
The stomach has many layers. The inner layer is called the mucosa which is rich in glands that secrete acids and inactive enzymes such as pepsinogen into the stomach cavity. Pepsinogen is activated by hydrochloric acid. The mucosa has gastric pits with parietal cells and chief cells emptying into the pits. The parietal cells secrete hydrochloric acid and the chief cells secrete pepsinogen. External to the mucosa is the submucosa and this layer has many blood vessels imbedded in connective tissue. Beyond this is the muscularis. In the stomach there are three layers of the muscularis. These are the oblique layer, circular layer, and longitudinal layer. The most external layer is the serosa (also known as the visceral peritoneum) and this is next to the abdominal cavity. Label the parts of the stomach and color them in. Color the layers of the muscularis using different colors of red or pink for each layer. Color the general regions of the stomach different colors along with the separate sphincters.
Muscularis layers m..
Answer Key: a. Fundus, b. Cardia, c. Lesser curvature, d. Longitudinal layer (of muscularis), e. Circular layer (of muscularis), f. Oblique layer (of muscularis), g. Body, h. Rugae, i. Greater curvature, j. Pyloric canal, k. Pyloric sphincter, I. Antrum, m. Gastric pit, n. Chief cell, o. Parietal cell, p. Mucosa, q. Submucosa, r. Serosa
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.