| While caffeine primarily is active in the brain and muscles, theophylline is active in stimulating the respiratory system, heart and kidneys. |
| Bronchial asthma is a respiratory system condition in which the air tubes to the lungs become especially vulnerable to constriction. |
| Breathing problems are considered to be those that affect the respiratory system below the vocal cords. |
| All of this breathing couldn't happen without help from the respiratory system, which includes the nose, throat, voice box, windpipe, and lungs. |
| The respiratory system is formed of two series of appendages, as found beneath the thorax. |
| Breathing in a lungful of Tehran air is a full-frontal assault on the respiratory system. |
