Digestive System

Anatomic Model Of The Internal Structures Of The Head And The Neck Of An Adult Human Body Left Lateral View Of A Median Section. The Mouth Is The Starting Point Of The Digestive Tract. Its Opening Is Controled By The Orbicularis Oris Muscle Of The Lips In Red. At The Time Of The Food Intake, The Tongue Moves Downwards By The Action Of The Underlying Genioglossus Muscle 2. The Palate, Roof Of The Oral Cavity, Includes A Bony Part, The Hard Palate 3, Made Of The Upper Jaw And The Palatine Bones, And The Soft Palate 4 Ending By The Palatine Uvula A. The Latter Moves Upward Or Downward To Selectively Close The Access To The Nose During Swallowing Or To The Mouth During Breathing. On The Level Of The Palate Lie Two Masses Of Lymphoid Tissue, The Palatine Tonsils 5 ; They Destroy The Pathogens Present In Ingested Food. Under The Genioglossus Muscle, The Geniohyoideus And Mylohyoid Muscles Allow Swallowing ; They Are Connected To The Mandible Bone Of The Lower Jaw And To The Hyoid Bone. The Swallowed Food Goes Then In The Fauces, Opening Between The Oral Cavity And The Pharynx. This One Is Composed Of The Nasopharynx, Communicating With The Nasal Cavity, And Of The Oropharynx, In Contact With The Oral Cavity And Continuous With Both The Larynx And The Esophagus In Brown. The Nasopharynx Also Connects With The Ear Via The The Eustachian Tube Aperture Above The Soft Palate. Behind The Nasal Cavities, The Nasal Conchae Superior, Middle And Inferior Filter The Inhaled Air To Pick Up The Odorant Molecules. The Larynx Joins Anteriorly The Pharynx At The Trachea ; It Extends In Front Of The Fourth To Sixth Cervical Vertebrae. Its Wall Includes Several Cartilages, Among Which The Epiglottic Below The Genioglossus Muscle, Thyroid Then Cricoid Cartilages In Light Blue. The Thyroid Cartilage, Forming The Adam's Apple, Binds To The Hyoid Bone In Beige Through The Thyrohyoid Membrane In (Photo By BSIP/UIG Via Getty Images)