Comparison of the avian 'unidirectional' respiratory system (a) where gases are exchanged between the lungs and the blood in the parabronchi, and the bidirectional respiratory system of mammals (b) where gas exchange occurs in small dead-end sacs called alveoli (From: West et al. 2007).s a result, air coming into a mammal's lungs is mixed with 'old' air (air that has been in the lungs for a while) & this 'mixed air' has less oxygen. So, in bird lungs, more oxygen is available to diffuse into the blood (avian respiratory system).
The Power of Sympathy or The Triumph of Nature (1789) is a cautionary novel by William Hill Brown (1765-1793). It is based on an actual case of seduction and incest in col â¦ onial America. It is considered by many to be the first American novel.
Inside the Mind of a Liberal. By Elise Cooper. Mike Gallagher has recently written a new book, 50 Things Liberals Love to Hate. This book is both humorous and informative, written by someone who has been a radio talk show host for over thirty years.