The oesophagus is a hollow muscular tube, also known as the food pipe or gullet. It is a connecting tube between the mouth and the stomach. It is located behind the trachea. The oesophagus consists of four coats of tissues. The movement of the tissue layers is responsible to move the food towards the stomach from the pharynx.
The stomach is the main part of the digestive system. It is also called food storage-tank of the body. It is a muscular, hollow organ that is open at both the ends. It lies between the oesophagus and the duodenum (the first part of the small intestine). While storing the food temporarily, muscular contractions of the stomach mix the food with the digestive juices. The digestive juices contain several enzymes that digest the food.
The pyloric sphincter is a narrow, thick ring of smooth muscle located at the bottom of the stomach. The two important functions performed by the pyloric sphincter are: (1) it controls the movement of the stomach contents from the stomach into the duodenum and (2) it maintains healthy functioning of the digestive tract. The pyloric sphincter is actually a valve that regulates digestion.
Peristalsis : The contraction of muscles in order to move something, in case of oesophagus. It is the movement of food towards the stomach.