From the inside out they are called: mucosa, submucosa, muscularis, and serosa. Blood vessels and lymphatic vessels present in this layer provide nutrients to the epithelial layer, distribute hormones produced in the epithelium, and absorb end products of digestion from the lumen. Reflect upon the structure of the bowel layers itself and describe the role each of these layers has in relation to peristalsis. Describe the development of the body cavities 3. Temporary storage of bile produced by the liver. The lamina propria lies outside the epithelium. lamina propria. Within the mouth, the teeth and tongue begin mechanical digestion, whereas the salivary glands begin chemical digestion. It is composed of two different regions: the parietal peritoneum, which lines the abdominal wall, and the visceral peritoneum, which envelopes the abdominal organs (Figure 23.1.3). Four compounds possessed EC50 values less than or equal to 11 M. The Nervous System and Nervous Tissue, Chapter 13. This process of rapid renewal helps preserve the health of the alimentary canal, despite the wear and tear resulting from continued contact with foodstuffs. Intrinsic innervation of much of the alimentary canal is provided by the enteric nervous system, which runs from the esophagus to the anus, and contains approximately 100 million motor, sensory, and interneurons (unique to this system compared to all other parts of the peripheral nervous system). Being able to predict the churn rate is the key to success for the telecommunication industry. describe the four layers of the gi tract There are 4 layers in gastrointestinal tract: from inside to outside these are mucosa, submucosa, muscular layer and serosa. 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The enteric nervous system provides intrinsic innervation, and the autonomic nervous system provides extrinsic innervation. Each layer has a different function and quality, which makes it unique. Present only in the region of the alimentary canal within the abdominal cavity, it consists of a layer of visceral peritoneum overlying a layer of loose connective tissue. Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor cells located on taste buds in the oral cavity, mostly on the tongue.Taste, along with olfaction and trigeminal nerve stimulation (registering texture . Accessory digestive organs comprise the second group and are critical for orchestrating the breakdown of food and the assimilation of its nutrients into the body. It is part of the digestive tract, located between the esophagus and the duodenum. The contractions of these layers promote mechanical digestion, expose more of the food to digestive chemicals, and move the food along the canal. Name the four layers of the digestive tract from superficial to deep. This system exhibited good correlation (r = 0.998) with a slope of 0.989 and intercept of 0.827, displaying good agreement with reference methods and existing parameters present on the market, i.e., YSI 2300 whole blood/plasma analyzer (Yellow Springs . Large intestine. Table 23.1 gives a quick glimpse at how these other systems contribute to the functioning of the digestive system. Starting from the lumen and moving outwards, these layers are the mucosa, submucosa, muscularis, and serosa, which is continuous with the mesentery (see Figure 23.1.2). Within the mouth, the teeth and tongue begin mechanical digestion, whereas the salivary glands begin chemical digestion. Only then does the blood drained from the alimentary canal viscera circulate back to the heart. The gallbladder releases bile, which is responsible as a buffer and emulsification, while the pancreas provides enzymes that break down starches, lipids, nucleic acids & proteins. Describe the orientation of smooth muscle fibers in the muscularis externa of the digestive tract. In the stomach. Describe the arrangement and subdivisions of the thorax 5. Food enters the mouth, is digested, and used for energy and nutrients; what cannot be used is expelled from the body. This venous network takes the blood into the liver where the nutrients are either processed or stored for later use. The mucosa surrounds the lumen, or open space within the digestive tube. The membrane consists of epithelium, which is in direct contact with ingested food, and the lamina propria, a layer of connective tissue analogous to the dermis. epithelium. Each hematocrit specimen was spiked to obtain four glucose concentrations (50-500 mg/dL). Differentiate between the primary dentition and the secondary dentition. It is made up of three layers: the epithelium, lamina propria, and muscularis mucosae. The wall of the digestive tract has four layers or tunics: Mucosa Submucosa Muscular layer Serous layer or serosa The mucosa, or mucous membrane layer, is the innermost tunic of the wall. Instead of serosa, the mouth, pharynx, and esophagus have a dense sheath of collagen fibers called the adventitia. Of these, eugenol, had an EC50 of 1.3 M against EBOV and is present in several plants including clove, cinnamon, basil and bay. The secretions of the associated glandular organs, such as the salivary glands, pancreas, liver, and gall bladder, aid the GI tract in accomplishing these functions. It includes blood and lymphatic vessels (which transport absorbed nutrients), and a scattering of submucosal glands that release digestive secretions. Thus, the challenge is to predict the churn percentage of customers with higher accuracy without comprising the profit. ANATOMY AND PHYSIOLOGY Individual Components of the Gastrointestinal System Oral cavity The oral cavity or mouth is responsible for the intake of food. 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The submucosal plexus (plexus of Meissner) lies in the submucosal layer and is responsible for regulating digestive secretions and reacting to the presence of food (see Figure 23.1.2). What might occur that could result in the autonomic nervous system having a negative impact on digestion? 1999-2023, Rice University. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Even so, the mortality rate still ranges from 30 to 40 percent. Notice that the epithelium is in direct contact with the lumen, the space inside the alimentary canal. 10. The first group is the organs that make up the alimentary canal. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix. Which is more efficient in propelling intestinal contents along the digestive tract: peristalsis or segmentation? Mucosa Alone among the GI tract, the stomach has a third layer of muscularis externa. From the inside out they are called the mucosa, submucosa, muscularis externa, and serosa. The muscularis in the small intestine is made up of a double layer of smooth muscle: an inner circular layer and an outer longitudinal layer. It lines the lumen of the digestive tract. Since it lacks sarcomeres, it is nonstriated. It contains blood vessels, nerve endings, lymph nodules, and lymphatic vessels. The four layers of the alimentary or digestive tract are listed as: Serosa: It is formed of the mesothelium and is found at the exterior part of the canal. The smooth muscle is responsible for movement of food by peristalsis and mechanical digestion by segmentation. 1. Even so, the mortality rate still ranges from 30 to 40 percent. Name the structure connecting the pharynx to the stomach. The mucosa of the stomach is a simple columnar epithelium composed entirely of mucous cells that produce a protective layer of bicarbonate-rich alkaline mucus that clings to the stomach mucosa and protects the stomach wall from being damaged by acid and digested by enzymes. Describe the basic factors in diffusion and passive transport systems. In general, sympathetic activation (the fight-or-flight response) restricts the activity of enteric neurons, thereby decreasing GI secretion and motility. The easiest way to understand the digestive system is to divide its organs into two main categories. Specifically, the more anterior parts of the alimentary canal are supplied with blood by arteries branching off the aortic arch and thoracic aorta. By clicking on this link you can watch a short video of what happens to the food you eat, as it passes from your mouth to your intestine. 1. Identify the segments of the large intestine and the four regions of the colon. They transport the protein and carbohydrate nutrients absorbed by mucosal cells after food is digested in the lumen. Also called the gastrointestinal (GI) tract or gut, the alimentary canal (aliment- = "to nourish") is a one-way tube about 7.62 meters (25 feet) in length during life and closer to 10.67 meters (35 feet) in length when measured after death, once smooth muscle tone is lost. If a person becomes overly anxious, sympathetic innervation of the alimentary canal is stimulated, which can result in a slowing of digestive activity. These enteric neurons are grouped into two plexuses. In addition, the mucosa has a thin, smooth muscle layer, called the muscularis mucosae (not to be confused with the muscularis layer, described below). Peritonitis is life threatening and often results in emergency surgery to correct the underlying problem and intensive antibiotic therapy. Muscularis: composed of two layers of muscle tissue. Legal. The system is much more complex. The digestive tract, from the esophagus to the anus, is characterized by a wall with four layers, or tunics. These lymphocyte clusters are particularly substantial in the distal ileum where they are known as Peyers patches. Also present are goblet cells and endocrine cells. In the rest of the digestive tract, it consists of smooth muscle (three layers in the stomach, two layers in the small and large intestines) and associated nerve fibers. The Cardiovascular System: Blood Vessels and Circulation, Chapter 21. There are 4 layers in gastrointestinal tract: from inside to outside these are mucosa, submucosa, muscular layer and serosa. Interspersed among its epithelial cells are goblet cells, which secrete mucus and fluid into the lumen, and enteroendocrine cells, which secrete hormones into the interstitial spaces between cells. How does this change in consistency facilitate your gaining nutrients from food? The idea of this style focuses on last years' sudden surge in popularity for plants as dcor. Composed of 3 layers (epithelial, areolar connective, smooth muscle) Contains lymph tissue. The fibers lie parallel, in a longitudinal view of the digestive tract, the fibers of the superficial circular layer appear as round balls, the fibers of the deep longitudinal layer are spindle-shaped. The epithelium is the innermost layer and it is responsible for most digestive, absorptive, and secretory processes. Inflammation of the peritoneum is called peritonitis. The blood vessels serving the digestive system have two functions. Since the mucosa is the innermost layer within the GI tract, it surrounds an open space known as the lumen. bookmarked pages associated with this title. The thin filaments are anchored to dense bodies. The gastrointestinal (GI) tract is composed of four layers of tissue, known as tunics. The lamina propria is a layer of connective tissue that is unusually cellular compared to most connective tissue. Consider for example, the interrelationship between the digestive and cardiovascular systems. Submucosal- nerve network between the mucosa and submucosa. The blood vessels serving the digestive system have two functions. The gastrointestinal (GI) tract is composed of four layers of tissue, known as tunics. Fluid, Electrolyte, and Acid-Base Balance, Lindsay M. Biga, Sierra Dawson, Amy Harwell, Robin Hopkins, Joel Kaufmann, Mike LeMaster, Philip Matern, Katie Morrison-Graham, Devon Quick & Jon Runyeon, Next: 23.2 Digestive System Processes and Regulation, Creative Commons Attribution-ShareAlike 4.0 International License, Blood supplies digestive organs with oxygen and processed nutrients; absorption of nutrients, Endocrine hormones help regulate secretion in digestive glands and accessory organs, Skin helps protect digestive organs and synthesizes vitamin D for calcium absorption, Mucosa-associated lymphoid tissue and other lymphatic tissue defend against entry of pathogens; lacteals absorb lipids; and lymphatic vessels transport lipids to bloodstream, Skeletal muscles support and protect abdominal organs, Sensory and motor neurons help regulate secretions and muscle contractions in the digestive tract, Respiratory organs provide oxygen and remove carbon dioxide, Bones help protect and support digestive organs, Kidneys convert vitamin D into its active form, allowing calcium absorption in the small intestine, Apron-like structure that lies superficial to the small intestine and transverse colon; a site of fat deposition in people who are overweight, Anchors the liver to the anterior abdominal wall and inferior border of the diaphragm, Suspends the stomach from the inferior border of the liver; provides a pathway for structures connecting to the liver, Vertical band of tissue anterior to the lumbar vertebrae and anchoring all of the small intestine except the initial portion (the duodenum), Attaches two portions of the large intestine (the transverse and sigmoid colon) to the posterior abdominal wall, Describe the organs of the alimentary canal from proximal to distal, and briefly state their function, Identify the accessory digestive organs and briefly state their function, Describe the four fundamental tissue layers of the alimentary canal and the function of each layer, Contrast the contributions of the enteric and autonomic nervous systems to digestive system functioning, Explain how the peritoneum anchors the digestive organs. Choose a modest trial pack with just two or four candies if you want to try these gummies out quickly. A) Mucosa- The mucosa, or innermost of the GI tract, is a mucous membrane. The visceral peritoneum includes multiple large folds that envelope various abdominal organs, holding them to the dorsal surface of the body wall. Citation: Nigam Y et al (2019) Gastrointestinal tract 4: anatomy and role of the jejunum and ileum. Even after development is complete, they maintain a connection to the gut by way of ducts. The hard palate, a bony structure, forms the roof of the mouth. Stomach. The mucosa is the innermost layer. The mucosa is the innermost layer, and functions in absorption and secretion. We recommend using a 2023 Course Hero, Inc. All rights reserved. By the end of this section, you will be able to: The function of the digestive system is to break down the foods you eat, release their nutrients, and absorb those nutrients into the body. What are the layers of mucosa? Small intestine. Explain how the enteric nervous system supports the digestive system. For example, when an ulcer perforates the stomach wall, gastric juices spill into the peritoneal cavity. Accessory digestive organs, despite their name, are critical to the function of the digestive system. Although the small intestine is the workhorse of the system, where the majority of digestion occurs, and where most of the released nutrients are absorbed into the blood or lymph, each of the digestive system organs makes a vital contribution to this process (Figure 23.1.1). The GI tract contains four layers: the innermost layer is the mucosa, underneath this is the submucosa, followed by the muscularis propria and finally, the outermost layer - the adventitia. When viewed from above, because of internal reflection, the light source makes a disc of light on the water's surface. secretory function in stomach. Bone Tissue and the Skeletal System, Chapter 12. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . EpitheliumIn the mouth, pharynx, esophagus, and anal canal, the epithelium is primarily a non-keratinized, stratified squamous epithelium. The stomach is a key part of the gastrointestinal (GI) tract, sitting between the esophagus and duodenum. A&P: Chapter 38 Section: Organization of the Digestive System Awarded 25 points out of 25 possible points. Mucosa - Circular muscle layer and longitudinal muscle layer are the two sublayers. Esophagus. There are two types of epithelial membranes, mucous membrane and serous membrane. It has four parts- cardiac, fundus, body and pyloric portion. In general, sympathetic activation (the fight-or-flight response) restricts the activity of enteric neurons, thereby decreasing GI secretion and motility. Name the major functions of the large intestine. Only through the process of absorption do the nutrients in food enter into and nourish the bodys inner space.. Deeper connective tissue which supports the mucosa The organs of the alimentary canal are the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. Inflammation of the peritoneum is called peritonitis. As soon as food enters the mouth, it is detected by receptors that send impulses along the sensory neurons of cranial nerves. In addition, the mucosa has a thin, smooth muscle layer, called the muscularis mucosa (not to be confused with the muscularis layer, described below). Mucosa: epithelium - secretion and absorption; lamina propria - nutrient absorption; muscularis muscosae - increases surface area (for digestion & absorption) 2. submucosa: receive absorbed food molecules 3. The blood vessels second function is to supply the organs of the alimentary canal with the nutrients and oxygen needed to drive their cellular processes. In turn, the digestive system provides the nutrients to fuel endocrine function. Table 23.1 gives a quick glimpse at how these other systems contribute to the functioning of the digestive system. The mucosa, composed of simple epithelium cells, is the innermost layer of the gastrointestinal (GI) tract. At the same time, the digestive system provides nutrients to the heart muscle and vascular tissue to support their functioning. The celiac trunk services the liver, stomach, and duodenum, whereas the superior and inferior mesenteric arteries supply blood to the remaining small and large intestines. Support/stabilize the organs of the abdominopelvic cavity and route for blood. The four major layers of the GI tract are: the innermost layer is the mucosa, next to it is the submucosa, then comes the muscular View the full answer Transcribed image text: Describe the four major layers of the GI tract that are found from esophagus to anus. What is the importance of the mesenteries? They transport absorbed fatty acids that cannot enter blood capillaries. Rather, this blood is diverted to the liver where its nutrients are off-loaded for processing before blood completes its circuit back to the heart. The layers are discussed below, from the inside lining of the tract to the outside lining: The epithelium is the innermost layer of the mucosa. Along the way, note how the food changes consistency and form. The serosa is a smooth membrane consisting of a thin layer of cells that secrete serous fluid, and a thin layer of connective tissue. The main function of the organs of the alimentary canal is to nourish the body. A sheet of mesentery that is remnant of the ventral mesentery, between the liver and the anterior wall of the peritoneal cavity. These tissues serve to hold the alimentary canal in place near the ventral surface of the vertebral column. The Cardiovascular System: The Heart, Chapter 20. Only through the process of absorption do the nutrients in food enter into and nourish the bodys inner space.. The lamina propria also serves an immune function by housing clusters of lymphocytes, making up the mucosa-associated lymphoid tissue (MALT). Between those two points, the canal is modified as the pharynx, esophagus, stomach, and small and large intestines to fit the functional needs of the body. The serosa is the portion of the alimentary canal superficial to the muscularis. Describe the mechanical and chemical digestion of food entering the stomach Describe any absorption that happens in the stomach Although a minimal amount of digestion occurs in the mouth, chemical digestion really gets underway in the stomach, primarily as the initial site of protein digestion. In general, the GI tract is composed of. describe the four layers of the gi tractcabo marina slip rates. Notice that the epithelium is in direct contact with the lumen, the space inside the alimentary canal. Name the four types of teeth and the three main parts of a typical tooth. They transport the protein and carbohydrate nutrients absorbed by mucosal cells after food is digested in the lumen. Note that during fetal development, certain digestive structures, including the first portion of the small intestine (called the duodenum), the pancreas, and portions of the large intestine (the ascending and descending colon, and the rectum) remain completely or partially posterior to the peritoneum. These intestinal veins, constituting the hepatic portal system, are unique in that they do not return blood directly to the heart. Epithelial cells have a very brief lifespan, averaging from only a couple of days (in the mouth) to about a week (in the gut). Swollen veins in the rectum that may result from straining during defecation. Its functions are to mix food with stomach acid and break food down into smaller particles using chemical and mechanical digestion. The third layer with high autonomy is defined as semiautonomous navigation, transferring the decision priority to the system. Except where otherwise noted, textbooks on this site A: The alimentary canal is defined as the narrow muscular tube by which food enters and solid wastes Q: From the esophagus to the anal canal, the walls of the digestive tract are made of the same four A: The digestive tract consists of mouth, esophagus, stomach, small intestine, and large intestine. The digestive system includes the organs of the alimentary canal and accessory structures. clinicalanatomy.com/mtd/382-layers-of-the-gi-tract, Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36. On the mucosa layer, small finger-like projections called villi and microvilli help to increase surface area for nutrient absorption. The wall of the alimentary canal is composed of four basic tissue layers: mucosa, submucosa, muscularis, and serosa. In turn, the digestive system provides the nutrients to fuel endocrine function.