Anatomy and Physiology II Practice Test

What are the four layers of the intestinal wall from inside out?

1. Serosa, mucosa, submucosa, muscularis

2. Mucosa, submucosa, muscularis, serosa

3. Muscularis, serosa, submucosa, mucosa

4. Submucosa, mucosa, muscularis, serosa

The correct answer is: Mucosa, submucosa, muscularis, serosa

The correct sequence of layers in the intestinal wall from the inside out is mucosa, submucosa, muscularis, and serosa. The mucosa is the innermost layer, which comes into direct contact with the intestinal lumen. This layer is important for absorption and secretion and consists of epithelial cells, lamina propria, and muscularis mucosae. Following the mucosa is the submucosa, which contains connective tissue, blood vessels, and nerves, providing support and a pathway for vessels and nerves to reach the mucosa. Next is the muscularis layer, comprised of smooth muscle that enables the peristaltic movements essential for propelling food through the intestines. Lastly, the outermost layer is the serosa, a protective membrane that covers the outside of the intestines and helps reduce friction with surrounding organs. This layered structure allows for efficient processing and movement of food, as well as providing necessary support and protection to the intestine. Understanding these layers is crucial for recognizing how the intestine functions and how it can be affected by various diseases.