Diegstive Tract-revised

Student’s Name
Professor’s Name
Course Title
Date of Submission
All organisms including invertebrates require nutrients for survival because they facilitate the metabolic activities of the body tissues. These nutrients are retrieved from food ingested that is broken down in the digestive system until the excess is excreted as feces. The digestive tract of invertebrates such as insects differs from those of other species in the same category whereby the functional structure is suited to ensure the organism is fed to facilitate metabolic activities. Such differences are observed in invertebrates such as porifera, cnidarian and the deuterostomes.
The organisms classified as invertebrates have gastrovascular cavities such as the cnidarian while others such as the earthworms have the alimentary canal. The digestive tract is modified to meet the nutritional needs of the organisms. Those with the gastrovascular cavities like those of the cnidarian have only one opening that serves as the mouth and the excretory hole at the same time. The food is digested as soon as it is ingested by enzymes secreted by the boy cells (Laufer, Siddall, and Graf 134). The earthworm, on the other hand, has two openings and the alimentary canal is the primary digestive organ. They have two openings whereby one is the month and the other is for excretion of feces after the digestion process has taken place.
It therefore follows that the size of the organism consumed by the invertebrates will depend on the size of opening (mouth and the length of the esophagus.

Since most are small, they often breakdown food outside the body through a process referred to as extracellular digestion. As mentioned earlier, invertebrates have different digestive organs and this will also determine how big the source of food the organism will consume to stay alive.Work Cited
Laufer, Alison S., Mark E. Siddall, and Joerg Graf. “Characterization of the digestive-tract microbiota of Hirudo orientalis, a European medicinal leech.” Applied and environmental microbiology 74.19 (2008): 6151-6154.