PHR1031 Chapter Notes - Chapter 8: Prostaglandin, Myenteric Plexus, Defecation
8 Jul 2018
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The digestive tract has four main tissue layers and two nerve layers (figure 1): Week 8: tissue layers, mucosa, submucosa, muscularis externa, serosa, nerve layers, myenteric plexus (auerbach"s plexus, submucous plexus (meissner"s plexus) The submucosa is a thick layer of connective tissue. It provides the digestive tract with distensibility (able to be dilated) and elasticity. The submucous plexus (nerve layer; pink layer in. Figure 4) lines the outside of the submucosa, and blood and lymph vessels are found in the submucosa. In the intestine, the mucous secreting glands are also found in this layer. The smooth muscle layer, or muscularis externa, is composed of two parts - an inner layer of circular smooth muscle and an outer layer of longitudinal smooth muscle (figure 5). This layer of smooth muscle is responsible for the peristaltic movement of the gastrointestinal tract (movement and mixing). The serosa is the outermost layer of the gastrointestinal tract wall.
