The digestive system!!!!!

This week in class we started talking about the digestive system. We discussed the GI tract. The GI tract goes from the oral cavity to the anal cavity. This GI tract is made up of four different layers of tissues. The four layers are mucosa, submucose, muscularis, and serosa. That is the order of the layers from the deepest to the most superficial.
The mucosa :: This is the inner lining of the GI tract. It is a mucous membrane that is composed of a layer of epithelium. This epithelium in the mouth, pharynx, esophagus, and the anal canal, is a mostly nonkeratinized stratified squamous epithelium. This functions as a protector. In the stomach and intestines is a simple columnar epithelium layer that functions in secretion and absorption. The mucosa also has a layer of areolar connective tissue known as the lamina propria. This layer has many blood and lymphatic vessels. These vessels are the routes in which nutrients that have been absorbed into the GI tract reach the other tissues of the body. This layer is responsible for supporting the epitelium and binding it to the muscularis mucosae. The third layer of the mucosa is the muscularis mucosae. This is a layer of smooth muscle fibers. This layer creats a fold in the mucous membrane of the stomach and small intestine. This helps to boost the surface area for digestion and absorption. This layer is avascular and has no blood supply.
The submucosa :: The submucosa layer has areolar connective tissue that helps bind the mucosa to the muscularis. It has many blood and lymphatic vessels that receive the absorbed food molecules. The submusocsa may have glands and lymphatic tissue. In this layer there is also an extensive network of neurons know as the submucosal plexus. This layer is highly vascular. It has clusters of white blood cells to recognize pathogens.
The muscularis :: The muscularis in the mouth, pharynx, and superior and middle parts of the esophagus has skeletal muscle. This muscle produces voluntary swallowing. This skeletal muscle also makes up the external anal sphincter. This permits voluntary control of defercation. For the rest of the tract, the muscularis has smooth muscle that is found in two sheets. There is a sheet of circular fibers and and outer sheet of longitudinal fibers. The food is broken down by the invouluntary contractions of the smooth muscle. The food is then mixed with digestive secretions. It is propeled along the rest of the tract.
The serosa :: The serosa is a serous membrane containing areolar connective tissues and simple squamous epithelium. This layer secretes a slippery/watery fluid that allows the tract to glide easily against the other organs. The serose inferior to the diaphragm, is known as the visceral peritoneum. This is becuase it forms a portion of the peritoneum.
Some other important words that we talked about are the following. The esophagus is what directs food to the stomach. The pyloric region leads to the small intestine. The true sphincter contains smooth or skeletal muscle cells that control the opening. The stomach is a "mixing bag" that works to mechanically digest food particles.
There are many things you can do to make sure you have and can maintain a healthy digestive system. Some of those things include eating healthy, exercising regularly and reduce or manage stress levels. Everything you eat and even drink needs to be broken down. The molecules are to big to just go trough the body.