Apple Snails
Apple snails are very interesting creatures with a complex digestive system. When an apple snail obtains food, it goes through its mouth and the break up begins using a raduala, a tongue-like structure that has on it microscopic hooks called cuticulae that are similar to teeth. The food is taken into the snail with this raduala and into the buccal cavity, where there is a set of muscular jaws that bite off the food particles. At the back of the buccal cavity there are saliva gland that aid in the breakdown by producing an acid called mucopolysaccharide. Saliva glands lie against the esophagus coating it with this acid as the food moves to the crop, a place in the snail where ground food is stored. The food then continues to a 3-part stomach that is covered by the digestive or midgut gland. This gland mixes the food with digestive enzymes and slime. Then the particles are pushed through the intestine. Larger food particles are filtered out by the entrance, but in the intestine the walls are covered with cilia and add more enzymes to finish the break down and absorption of nutrients. When the rest of the particles pass through the intestine they go to the anus where undigested waste in finally released.
Little Neck Clams
Little neck clams are many of the clams that you see on the beach or even eat at a restaurant. They are a lot more complex than you think in surving the ocean world. A Little neck clam obtains its food by absorbing H2O. The water goes through the clam's gills and by capturing oxygen the clam obtains food such as plankton. Mucus in the gills begin trap the food and tiny hairs called cilia move it toward palps or "fleshly lips" around the mouth that sort the food. Food is consumed down the esophagus into digestive gland where enzymes begin to decompose the food and absorb its nutrients. Waste that is created is passed to the anus and released through the clam's siphon.
Giant Squids
Giant squids are carnivorous creatures that roam the ocean. They consume whales, sharks, and many other sea organisms in their diet, but where does it all go. The complete digestive system of a Giant squid contains a mouth, a complex stomach, and an anus. To digest in the first place Giant squid first obtain food. The digestion process starts when the food is carried into the mouth cavity, where just as the snail, contains a raduala (row of teeth) that begins the breakdown of food. This food then passed directly through the brain and then to the stomach where the process continues. The stomach is lined with cells and digestive glands that break down the food and eventually move it to the caecum, or beginning of the large intestine. After passing through here the rest of the food particles go to the Giant Squid's liver and here absorption of nutrients to be passed into the blood of the organism happens. Any materials that are undigested or that cannot be digested are compressed and are released through the anus to the mantle cavity and then out of the creature into open water.