Why the respiratory system of birds is more efficient than that of humans and other mammals

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In this respiratory physiology video the respiratory system of birds is compared to that of mammals. The differential characteristics of the respiratory system of birds that make it so efficient are explained. For example, the ratio between lung surface area and body surface area is 10 times greater in birds than in mammals. They have compact and rigid lungs, specialized in gas exchange. They have 3° bronchi (parabronchi) from which emerge atria, infundibulum and, finally, air capillaries with unidirectional air circulation. Unlike mammals, they lack respiratory bronchioles, alveolar sacs and alveoli through which air circulates bidirectionally (it enters on inspiration and leaves on expiration). Hematosis occurs between air and blood capillaries by a respiratory membrane that is thinner than that of mammals because the basal membranes of the respiratory epithelium and capillary endothelium fuse. Ventilation depends on the air sacs that provide a continuous flow of fresh air through the lung. Which allows hematosis (gas exchange) to occur both during inspiration and expiration.

[@leandrofernandez6722]

Muy buen video, mis felicitaciones! De paso una pregunta, hay evidencia de que los dinosaurios no aviares poseían este tipo de sistema respiratorio, y si de alguna manera les dió ventaja evolutiva frente a otros vertebrados?

[@mauriciogiuliodori]

Muchísimas gracias por comentar y muy buena tu pregunta Leandro! Honestamente excede mi área de conocimiento. No sé nada de evolución. No soy biólogo. Saludos