It is 10 inches long and connects the Pharynx to the stomach. The oesophagus runs parallel to the trachea and is narrowed at three points, behind the cartilage of the trachea, where the left bronchus and aorta cross in front of the oesophagus and where the oesophagus enters the stomach. The main function of the oesophagus is to transport the bolus from the oral cavity down into the stomach. The movements of the bolus are caused by peristalsis. The salivary amylase continues to act throughout the journey. Peristalsis moves the bolus down through the oesophagus. Peristalsis is carried out behind the Bolus or Chyme, the inner circular muscle contracts (and the longitudinal muscle relaxes), pushing material in front of it. In front of the material, the circular muscle relaxes and the longitudinal muscle contracts, to hold the tube open to receive the food. Two sets of muscles acting in this way are said to be antagonistic. Inside the oesophagus there are no secretions, the salivary amylase aids the journey but nothing is secreted during the travelling of the …show more content…
It is continuous with the oesophagus at the cardiac sphincter and the duodenum at the pyloric sphincter. It is divided into three sections, the fundus, body and the antrum. The walls of the stomach are made up of muscle layer (longitudinal, circular and oblique muscle), submucosa and mucosa. There are many functions of the stomach, it is a temporary storage area for the food to allow digestive enzymes to act. These break down the food molecules so they are ready for the intestines. It functions to do the mechanical breakdown and production of Chyme. The stomach walls roll and churn the food around and pour on secretions from the gastric glands. The resulting paste-like material is called Chyme. Another function of the stomach is to prepare ions for digestion further down the alimentary canal. Finally, the stomach regulates the moving of contents (gastric) into the Duodenum. The muscles in the stomach wall roll and this helps the Bolus to move around and churn. The gastric glands pour out their secretions and this then leaves Chyme. The stomach then empties the contents into the Duodenum. Gastric glands produce gastric juice that contains gastric protease and hydrochloric acid. The gastric protease