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.
structure of upper respiratory system. conists of two parts: upper respiratory system-includes nose, pharynx, and associated structures lower respiratory system-includes larynx, trachea, bronchi, and lungs.nclude nose, pharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles, their function is to filter, warm, and moisten air and conduct it into the lungs respiratory zone-consists of tissues within the lungs where gas exchange occurs.