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.
For other uses, see Sympathy (disambiguation). Sympathy (from the Greek words syn together and pathos feeling which means fellow-feeling) is the perception, understanding, and reaction to the distress or need of another life form. This empathic concern is driven by a switch in viewpoint, from a personal perspective to the perspective of another group or individual who is in need.