What are the types of digestion and of digestive system of platyhelminthes?
The digestive system of flatworms is incomplete, not fully developed, yet more advanced than in any other simple livings, therefore, they complete their digestion by means of extracellular and intracellular activity.
The complete digestive system of the flatworms consists of mouth, a tube similar to pharynx and the intestine that could be branched to enlarge the area of absoption of nutrients. We notice that the dygestive system presents a single opening, therefore the wastes are eliminated through the same place the food enters into the pharynx, such as, in flatworms, the mouth plays also the role of anus.
There is another complementary way through flatworms excrete materials that they do not need anymore, namely flame cells.