Fats, such as the fats in milk, need to be digested by your body. They are broken down into fatty acids and glycerol by an enzyme called lipase. Gastric lipase, secreted by the stomach lining, has a pH value for optimal activity around neutrality and would appear, therefore, to be essentially inactive in the strongly acid environment of the stomach.
The structures of your upper respiratory system are always working overtimeâfiltering air, expelling pollutants, and relying on other anatomy to remain healthy and intact. Let's take a look at some of the structures and jobs of the upper respiratory system. Nasal Cavity The nasal cavity is a chamber of the internal nose that connects to the nasopharynx. Air is inhaled through the nostrils and warmed as it passes through the nasal cavities.
Air flow Sequence. The sequence in which incoming air flows through the upper respiratory tract is as follows: 1  Normally air enters the respiratory system through two external nares (openings of the nose) and proceeds through the nasal cavity and sinuses. 2  Air is warned, filtered, and moistened.ntroduction. The respiratory system consists of the nose, nasal cavity, pharynx, larynx, trachea, bronchial tree, and the lungs. Its primary function is the basic exchange of oxygen and carbon dioxide.