The<unk>  (plural:<unk> es) is an organ found in vertebrates and invertebrates, though the structure is not universally the same across the species. In humans the<unk>  is part of the digestive system and also of the conducting zone of the respiratory system. (The conducting zone also includes the nose, larynx, trachea, bronchi, and bronchioles, and their function is to filter, warm, and moisten air and conduct it into the lungs.) The<unk>  makes up the part of the throat situated immediately posterior to the nasal cavity, posterior to the mouth and superior to the esophagus and larynx. The human<unk>  is conventionally divided into three sections: the nasopharynx, the oropharynx and the laryngopharynx. It is also important in vocalization.
There are two sets of<unk> eal muscles that act upon the<unk> . These are arranged as an inner layer of longitudinal muscles and an outer circular layer.
Pharynx
Larynx
Throat
Nasopharynx
Nasal cavity
Upper respiratory tract
Airway
Neck