BIOB34H3 Lecture Notes - Lecture 4: Gastrovascular Cavity, Foregut, Proventriculus
Document Summary
Digestion and absorption: gut development: animals form vis the blastula and gastrula stages, the central cavity (spongocoel) is the same cavity that forms during gastrulation. Sponges don"t use this cavity for digestion but they call it the paragastic cavity: a hydra has the same basic body plan with an opening and central cavity. Cnidarians use this cavity for digestion so its referred to as the gastrovascular cavity. One that"s the mouth and one that"s the anus. Animals with this can process many meals simultaneously because the system is flowing in one direction. In protostomes, the first opening that forms is the mouth then the anus forms second. Deuterostomes form the anus first then the mouth second. Most higher animals (like vertebrates) are like this. The more plant material an animal consumes, the larger the gut will be. For example, some iguanas have larger guts as they are herbivores while other iguanas have smaller guts as they are carnivores or omnivores.
