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.
See also: Respiratory tract. The respiratory system (called also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for the process of respiration in an organism.he passage of air into the lungs to supply the body with oxygen is known as inhalation, and the passage of air out of the lungs to expel carbon dioxide is known as exhalation; this process is collectively called breathing or ventilation.