A noncovalent bond between an electronegative atom (commonly oxygen or nitrogen) and a hydrogen atom covalently bonded to another electronegative atom. Particularly important in stabilizing the three-dimensional structure of proteins and formation of base pair s in nucleic acids.
Introduction[edit] The respiratory system serves three principal purposes in the human body: gaseous exchange; sound production; and assistance in compression of the abdomen. It can be divided into two structural divisions, upper and lower, as well as two functional divisions, conducting and respiratory.
Respiratory | Trachea, bronchioles and bronchi. The conducting portion is made up of: nasal cavities, nasopharynx, larynx, trachea, bronchii and bronchioles. The trachea branches to give rise to two primary (main) bronchii.These then branch successively to give rise in turn to secondary and tertiary bronchii.espiratory | Trachea, bronchioles and bronchi. The conducting portion is made up of: nasal cavities, nasopharynx, larynx, trachea, bronchii and bronchioles. The trachea branches to give rise to two primary (main) bronchii.