part of connected to develops from directly develops from Eumetazoa Homo sapiens system organ anterior region of body respiratory system digestive system circulatory system foregut chordate pharynx external carotid artery digestive tract maxillary artery artery pharyngeal arch artery 1 pharyngeal arch 1 cardiovascular system blood vasculature arterial system pharyngeal vasculature pharyngeal arch system main body axis body proper embryonic craniocervical region