 Dear students, in this topic, we shall discuss the parts of the elementary canal present in the head gut. Head gut is the anterior region of the elementary canal which receives food through ingestion. It consists of structures for feeding and swallowing. These parts include the buccal cavity and pharynx. The buccal cavity is the space behind the mouth. Mouth is an opening and the inner part is called buccal cavity. Buccal cavity has many associated structures. For example, mouth parts are jaws, teeth, tongue and slivery glands. Due to these parts, buccal cavity performs many functions. We shall discuss these functions one by one. The first function of buccal cavity is the selection of food. Buccal cavity selects food through taste and feeling. If taste or feeling is not good, then food is rejected and if it feels a good taste and feeling, food is swallowed. The second function of buccal cavity is to handle the food and masticate it. These processes involve teeth and tongue. Teeth are present in all vertebrates and are used for holding or tearing the prey or food. They also grind the food by a process which is called mastication. Tongue is also present in all vertebrates and assists in grasping, handling and rolling the food during the process of mastication. Tongue plays an important role during the process of mastication because it plays a role in handling and grasping the intake food or ingested food. It is also very important in the swallowing process. In addition, food selection also helps because it has taste buds which have gastatory chimo receptors. Buccal cavity has sliver glands which produce saliva. Sliver lubricates the food material. This lubrication assists in swallowing as well as in partial digestion of starch foods because saliva contains an enzyme which is called saliva amylase. Dear students, pharynx comes after buccal cavity. Pharynx's major function is swallowing. Swallowing is the process which allows the bolus of food formed after mastication to pass it from the buccal cavity into the esophagus. So pharynx is the bolus of food through a process which is called swallowing. Swallowing is a sensitive or highly integrated function which involves integrated movement of muscles of tongue and pharynx. It also involves peristaltic movements of esophagus. Swallowing occurs in many steps. First, the tongue pushes the bolus to the back of mouth. Then the soft palate or uveola moves upward and backwards which closes the nasal opening. After that, larynx moves upward and brings the epiglottis to a horizontal position. This process closes the glottis which is the opening of trachea. This is very important. The beginning of swallowing action is voluntary but once the food reaches the back of buccal cavity near the pharynx, swallowing becomes involuntary which is under the direct neural control of medulla oblongata of the brain.