BIO E105 Lecture Notes - Lecture 27: Trachea, Modes Of Mechanical Ventilation, Bronchus
Document Summary
How do vertebrate lungs work: a tube known as the trachea carries inhaled air to narrower tubes called bronchi. The bronchi branch off into even narrower tubes called bronchioles: the lungs, which enclose the bronchioles and part of the bronchi, are infoldings of the throat that function in gas exchange. Lung structure and ventilation vary among species: in addition to structural differences, the lungs of different species differ in mode of ventilation. In the simple lungs of snails and spiders, air movement takes place by diffusion only. Vertebrates actively ventilate their lungs by pumping air via muscular contractions. Lung structure and ventilation vary among species: one mechanism for pumping air is positive pressure ventilation, in which air is pushed into the lungs. Frogs use this mechanism to breathe: humans and other mammals pull air into their lungs via negative pressure ventilation.
