Digestive System
The digestive system is responsible for digesting the food that is ingested by the body. The digestive system removes energy and nutrients from the food it breaks down. Some of the major organs in the digestive system are the mouth, pharynx, epiglottis, esophagus, small intestine, large intestine, rectum and anus. The digestive system is connected to the Cardiovascular System through the common hepatic , gastric, mesenteric, and iliac arteries. the blood leaves the small intestine through the hepatic and iliac veins.
The mouth is responsible for the beginning stages of mechanical digestion. Inside the mouth the teeth chew the food, and the tongue forces it back toward the pharynx.
The Pharynx is the next stop on the digestive tract. The food travels through the pharynx (a transportation tube) and into the the esophagus. Air also travels through the pharynx, but is stopped from entering the esophagus by the epiglottis.
While in the pharynx the food passes by the epiglottis, a flap which prevents the food from entering the lungs.
From the pharynx the food enter the esophagus. The food, or bolus at this point is pushed along by a process called peristalsis. The smooth muscles that do the peristalsis push the bolus in a wave-like motion down into the stomach.
The stomach is located just beneath the diaphragm. The stomach is where chemical digestion begins. Hydrochloric acid is secreted in the stomach as well as pepsinogen, which is turned into pepsin, which digests proteins. The stomach breaks down the bolus into chyme, which is pushed, by peristalsis into the duodenum, the beginning of the small intestine.
The chyme enters the small intestine at the pyloric sphincter, the beginning of the duodenum and of the small intestine. The duodenum, jejunum, and illium make up the small intestine, the organ that does the majority of the body's digestion. Carbohydrates are digested by enzymes like dextrinase, maltase, sucrase, and lactase. Proteins are broken down by peptidases, nucleosidases, and phosphotases. The small intestine will absorb ninety percent of the nutrients as well as most of the water in its 21 feet of length. Anything that has not been digested and absorbed by the small intestine makes its way into the large intestine from the illium.
The large intestine is the last stage of the digestive system. The large intestine is composed of the ascending colon, the transverse colon, the descending colon, the sigmoid colon, the rectum, and the anus. The large intestine removes the excess water from the chyme and bacteria break it down farther. Once the chyme has been broken down as far as it will be it is called feces. The feces enters the rectum and leaves the body through the anus.
Skeletal System Lymphatic System Integumentary System Cardiovascular System
Muscular System Excretory System Nervous System Respiratory System
Reproductive System Endocrine System Digestive System Credits