Which layer of the digestive tract is in direct contact? There are three: the Epithelial cell layer, Circular muscle, and Submucosa. Which one is the most important? Here are the answers. In case you are still confused, here are some key differences between these layers. Hopefully this information will help you understand what each layer is responsible for. And you can use this knowledge to help you understand how different parts of the digestive tract work.

Submucosa layer

The mucosa is the innermost layer of the gastrointestinal tract. It surrounds the lumen of the digestive tract and comes into contact with the food being digested. The mucosa has three layers: the epithelium, lamina propria, and muscularis mucosae. The submucosa contains nerves, blood vessels, and elastic fibres with collagen, which stretch with increased capacity.

The muscular layer of the digestive tract is composed of two layers, the inner and outer, and is organized in circular rings around the tract. The inner ring is steep and shallow, and is in direct contact with the food consu. In both the submucosa and muscularis layers, coordinated contractions propel the food through the tract. In the stomach, the food is partially digested, and is called chyme. The semi-solid waste from the large intestine is called faeces.

Circular muscle layer

There are two layers of muscles in the digestive tract: the longitudinal and circular muscles. These muscles are connected by the Myenteric plexus and help propel food through the digestive tract. This movement, called peristalsis, is regulated by the enteric nervous system. The outer circular layer regulates the speed of movement while the inner circular layer serves as a resistance to peristalsis.

The gastroesophageal sphincter has a specialized muscle layer called the muscularis. The muscle layer has an innervation that is controlled by excitatory motor neurons. These muscle cells are responsible for mixing the food with digestive juices and facilitating absorption. The stomach is the most sensitive part of the digestive tract, so it is important to understand the function of each layer.

Muscle externa layer

The muscularis externa is the outer layer of the gastrointestinal tract. It consists of two layers: the inner circular layer and the longitudinal outer layer. Together, these two layers help propel food through the gastrointestinal tract. The muscle, located in the lower intestine, is controlled by the myenteric plexus. The colon is thicker than the rest of the digestive tract, because the feces are heavier. It also contains longitudinal ribbons called tiniae coli.

The muscularis externa layer of the digestive tract consists of three distinct layers. The inner circular layer breaks down food by contracting. The outer longitudinal layer is a helical structure, with different pitches. These two layers are coordinated by the myenteric plexus and Auerbach’s plexus. The autonomic nervous system controls peristalsis.

Epithelial cell layer

Epithelial cells are found on all surfaces of the body, including the skin and hollow organs. They play important roles in protecting the body from various diseases. Cells also form the lining of the respiratory tract and the digestive tract, where they are in contact with the food we eat. The epithelial cells also have other important functions, such as secretion and absorption. They allow the absorption of various substances from food, including vitamins and minerals.

The intestinal epithelial cells are the main players in amino acid absorption. They are highly polarized with the apical plasma membrane facing the intestinal lumen. IECs contain different types of transporters at their apical surface. Amino acids are transported into the cells and interstitial fluid through these transporters. Likewise, amino acids can enter blood vessels through the intestinal wall.

Muscle layer

In order for enzymes to function properly, they must come in contact with the food molecules. As a result, food ingested at the beginning of the digestive process is in large chunks that have a low surface area for the amount of volume. As a result, enzymes will only have access to a small proportion of the food, so it’s important to break down the food mechanically through mastication. Churning the food through the muscles of the small intestine and stomach is essential for enzyme activity. By splitting a 10 ml chunk into 8 pieces, you double the surface area and volume of the food.

Once you have swallowed a meal, your brain will send signals to the muscles of the esophagus to open. As the food reaches the lower esophageal sphincter, the muscle relaxes to let food pass into the stomach. Usually, the LES stays closed to prevent food from refluxing back into the esophagus. Next, the muscles of the stomach mix the food with digestive juices and empty it into the small intestine.


The digestive tract has several layers. The upper layer is called the serosa or adventitia, and the lower layer is known as the submucosa. Both layers are composed of inflammatory cells and lymphatics, while the submucosa contains lymphatic vessels, nerves, and mucus-secreting glands. These cells are responsible for regulating the flow of fluid and mucus in the digestive tract.

The innermost layer of the digestive tract is called the mucosa. It is the most complex in both structure and function. Food is absorbed from the mucosal surface. Mucosa consists of three layers: the epithelium on the outer surface, the mucosa propria on the inner side, and the muscularis mucosa, a smooth muscle layer lining the inside of the gastrointestinal tract.