The trachea, bronchi and bronchioles form the tracheobronchial tree â a system of airways that allow passage of air into the lungs, where gas exchange occurs.he trachea marks the beginning of the tracheobronchial tree. It arises at the lower border of cricoid cartilage in the neck, as a continuation of the larynx. By Bibi Saint-Pol [CC BY-SA 3.0], via Wikimedia Commons. Fig 1.0 â Overview of the tracheobronchial tree.
While relative masses are nice if you want to compare protons, neutrons and electrons to one another, it doesn't tell you what the actual masses of these particles are. In kilograms, the masses are: Neutron = 1.6749286*10-27 kg.
Atomic mass is the total mass of protons and neutrons in an individual atom or isotope. Atomic weight is the average mass of all of the naturally-occurring isotopes of an element. Both atomic mass and atomic weight are represented using a unit called the atomic mass unit (amu), which was defined using carbon's most common isotope, carbon-12.