A typhlosole is a fold on the dorsal, or top side, of the earthworm’s inner intestinal wall that runs along most of the length of the earthworm’s body. An important part of the earthworm’s digestive system, the typhlosole increases the surface area that the worm has available to efficiently absorb necessary nutrients from the food it digests. The typhlosole is not physically identical in different earthworms, and in fact, some earthworms do not have one at all. In addition, earthworms are not the only animals to have a typhlosole; other animals that exhibit a typhlosole include mollusks and oysters.
The digestive system of an earthworm can be separated into different regions, depending on function. These sections include the pharynx, esophagus and crop, as well as the gizzard and the intestine. The common earthworm has a high intake of organic materials as a primary source of food including soil, vegetation and even decomposing bodies of dead animals. At the same time, an earthworm can also digest inorganic materials as well. The types of foods an earthworm eats are important as they determine the nutrients that the animal absorbs and the wastes that it secretes.
When the earthworm eats, the pharynx is the part of the body that swallows the food. After the food passes through the pharynx, it travels through the esophagus where the earthworm’s body is rid of any excess calcium. When this process is through, the crop stores the food until it moves to the gizzard. The gizzard completely grinds the food by using stones that the earthworm also digested. Then, the ground food passes into the intestines where, among other digestive processes, the typhlosole works to absorb nutrients.
The earthworm can consume up to its own body weight in food on a daily basis and, thus, it needs a proper digestive system to effectively absorb nutrients. With a typhlosole, the earthworm is better equipped to accomplish this task. While absorption of nutrients is important, so is secretion of wastes. In fact, the secretion of wastes is beneficial for both the earthworm and its environment.
The digestive system of the earthworm is related to healthy soil and plant life. Just as the earthworm absorbs its nutrients, plants need their own nutrients to survive as well. It just so happens that after the earthworm absorbs its nutrients it secretes the waste into the soil. Nitrogen exists in the earthworm’s secretion and is, in itself, an important nutrient for plants.