Digestion and Digestive systems essays

Digestion and Digestive systems essays The digestive system is the part of the body responsible for acquiring nutrients and expelling wastes. This semester we dissected seven different animals, observing a different digestive system in each animal. As the dissected animals progressed from more primitive to more complex, the digestive systems also increased in complexity. The first animal dissected was the earthworm, which has a fairly basic digestive system. Food is ingested by the earthworm through the mouth, and then it passes through the small buccal cavity and the pharynx. From there, the food moved to the esophagus and then to the crop, where the food is moistened and stored for a short time. After leaving the crop, the food travels to the gizzard, which grinds the food before it enters the intestine. Nutrient absorption takes place in the intestine, and finally wastes are expelled at the anus. The digestive system of the mussel is slightly more complicated than that of the earthworm, due to the addition of the stomach and digestive glands. Food enters the mussel through the mouth, and then travels along a tube to the stomach. In the stomach, enzymes produced by the digestive gland are released to break down digestible material. In addition, the stomach is where undigesttible material is sorted out so that it passes through the intestine and out of the body through the anus. In the crawfish, you see an even more complex digestive system. Food enters the crawfish through the mouth, then travels down the esophagus to the stomach. The stomach of the crawfish is divided into two sections: the cardiac chamber and the pyloric chamber. Food enters the cardiac chamber from the esophagus, and it is then ground into small particles by the gastric mill. Food then enters the pyloric stomach, which contains bristles that strain out large pieces before they reach the intestine. While traveling through the intestine, the food is broken down by enzymes from the ...