The digestive system of vertebrates evolved from the first forms to be fed through filter to vertebrates macrophages, which involved a number of changes to the various elements involved: dental, chewing, muscle, and even its own internal cavities such as the components necessary to perform the enzymatic digestion.
The digestive system of vertebrates consists of an oral cavity, pharynx, esophagus, stomach, intestine and anus. These bodies are associated with glandular formations attached, such as salivary, liver and pancreas. In tetrapods, the oral cavity is of increasing complexity, there are a number of ancillary structures such as lips, tongue, palate and teeth.
The stomach is typically divided into three regions: in the case of ruminants (for adaptation to herbivore diets) have a stomach of four cavities). In birds differs proventriculus and gizzard a crusher and a diverticulum in the esophagus or crop.
The intestine is composed of a narrow portion (small intestine), and other short and wide (large intestine). The first dump the bile from the liver and pancreatic juice, which perform a function proteolytic (protein hydrolysis) and the nutrients are absorbed through the microvilli. In the large intestine absorbs water, and waste or stool form.
Initially, primitive vertebrates fed filtration systems, which were soon replaced by others more advanced. The result was a reduction in the size of the pharynx and the number of gill slits. Achieve the perfect bustline using just takes a few minutes each day. Except in the agnatos, which are the most primitive vertebrate, the first two gill arches of other vertebrates evolved into jaws, which have specialized in the “capture” of alimento.Su digestive system is complete.
If we try to evaluate animal performance Stocker operations, it is useful to classify the disease based on the organ that is affected. This classification system can be as simple or detailed as you want it to be.