The human digestive system is an enormously complicated series of organs and tissues. The GI tract runs from your mouth, where food goes in, to your rectum, where the processed food comes out. Everything in between, including your esophagus, stomach, small intestine, and large intestine, are all part of your GI system as well. The structure and function of digestive cells is therefore hard to summarize without the use of a very thick medical textbook. But let’s give it a try anyhow.
The mouth is the first part of the digestive system. Specialized cells on the tongue allow a person to taste. Salivary glands release saliva, which begins the digestive process, and allows food to slide down easier.
The next part of the digestive system is the esophagus. This is the muscular tube that connects the mouth to the stomach. The esophagus contains involuntary muscle what actively moves food and liquids down via contractions that take place when you swallow.
The stomach is the next stop for food you eat. The stomach is a very active organ, containing many different specialized cells that aid in digestion. Chief cells and parietal cells release various enzymes that help break down food in to molecular components.
The stomach empties in to the small intestine. This organ is many feet long and contains a variety of cells. Many of the cells in the small intestine have structures called “villi” on the surface. These structures serve to increase the surface area and help in absorption of nutrients. The digestive system also gets a boost from some chemicals that are transported from other areas, like bile from the liver and gallbladder. Bile helps break down fatty acids.
Most nutrients are absorbed by cells in the small intestine. There are actually three parts to the small intestine, the duodenum (structure and function details), illeum, and jejunum. Each of the three parts have slightly different cellular structure and are responsible for absorbing different vitamins and nutrients.
The next part of the digestive system is the large intestine. Although it is called “large”, it is actually quite a bit shorter than the small bowel. However, it is wider. Cells in the large bowel further process the food that you’ve eaten. At this point, most of the nutrients have been absorbed, but the last of them are also removed. The large bowel has a air amount of “helpful” bacteria that also help breakdown waste. A lot of water is reabsorbed in the large bowel. By the end of large bowel, the waste products have most of the water removed and reprocessed.
All along the small and large intestine are large ring-like muscles that help move food and waste along the chain – sort of like a conveyor belt. Failure of these cells to function properly can be a big problem.
Unfortunately, there just isn’t room here to go in to a lot of detail on the structure and function of digestive cells. The topic fills large chapter of anatomy and physiology textbooks. However, this should give you a good outline. The digestive system is quite complicated and takes many years of study to understand in great detail.