7 The longest intestine is possibly that of the blue whale. It reaches about 220 metres. Food is stored in our stomach for about 3 to 5 hours, while it can stay in our large intestine for about 6 to 20 hours. renal artery kidney renal vein ureter renal vein kidney renal artery bladder urethra THE DIGESTIVE AND URINARY SYSTEMS The digestive system The function of the digestive system is to break down food, release the nutrients, and absorb those nutrients into the body. The majority of digestion occurs in the small intestine, but each organ of the system takes part in the process. The system includes two types of organs: the large intestine, the final section of the digestive tract which stores and eliminates undigested waste and reabsorbs water. At intervals, the involuntary muscles within the walls of the large intestine propel solid waste material, called faeces, towards the rectum in a process called defecation. the accessory organs, such as the liver and the pancreas, which release essential substances for the digestive process through ducts. the alimentary canal, or digestive tract, which is a one-way tube of about 7.62 meters from the mouth to the anus , and which includes: the pharynx, a canal linked to the oesophagus where chewed food mixed with saliva, called bolus, is pushed into by the tongue (muscular organ that moves food around the mouth); the oesophagus, a muscular tube of about 25 cm long that carries food into the stomach; bladder: vescica to chew: masticare duct: dotto kidney: rene large intestine: intestino crasso liver: fegato small intestine: intestino tenue sore: piaga 24 BODY AND MIND two kidneys (bean-shaped organs) which extract waste from the blood, balance body fluids, and form urine; two ureters, which are the tubes that conduct urine from the kidney to the urinary bladder; the stomach, an expanded organ in the abdominal cavity which digests food thanks to enzymes and acids. The result, a semiliquid mixture of gastric juice and food, goes to the small intestine; the small intestine, the longest part of the alimentary canal which absorbs most of the nutrients from digested food. Digestive juices from the liver and the pancreas enter it through a small opening in the duodenum (hollow tube connecting the stomach to the small intestine) to end the process and pass on the remains to the large intestine; The urinary system The function of the urinary system is to remove waste from blood in the form of urine. It consists of: the bladder, which is a hollow organ that receives and stores urine; the urethra, which is a tube that takes urine outside for elimination. Oral cavity Tongue Mouth Pharynx Salivary glands Esophagus Liver Esophagus Sphincter Stomach Sphincter Gallbladder Pancreas Small intestine Large intestine Rectum Anus Small intestine