Avian respiration

Specialities in Birds respiratory system: Air sacs, specialized parabronchi , Unidirectional flow
Benifits of air sacs, Benefit of 2 respiratory cycles
Bird-like respiratory systems in dinosaurs
Rate of breathings in birds

1. Avian respiratory system

2. Avian respiratory system Delivers oxygen from the air to the tissues and removes carbon dioxide. thermoregulation

3. How Avian respiratory system differs from mammals? Presence of air sacs and air spaces Lungs structure Unidirectional flow

4. Air sacs Inconspicuous, but integral, part of the avian respiratory system… Air sacs are thin-walled structures… Extend into the body cavity and into the wing and leg bones…

5. Air sacs benefits Unidirectional flow of air Delivers huge quantity of O 2 Remove lethal body heat Protect internal delicate organs Interclavicular sac is essential for vocal sound production

6. unidirectional flow of air

7. Air sacs Mostly birds have 9 In weavers 6 7 in loons and turkeys 12 in shorebirds and strokes

8. Paired cervical air sacs Strutting sage grouse Frigate birds

9. Birds inhalation Birds inhale by lowering the sternum, which enlarges the chest cavity and expands the air sacs. Contraction of the sternum and ribs compresses the air sacs, pushes fresh air from them through the lungs, and exhales the air

10. Birds respiration

11. Parabronchi

12. Cross current exchange blood flow at 90 o to air flow Parabronchus Unidirectional air flow Pul. artery Pul. vein

13. Allows oxygenated blood that leaves the lung to have a higher oxygen tension than the oxygen partial pressure in exhaled air

14. Respiratory cycles "Inhaled air proceeds through two respiratory cycles that, together, consist of four steps. Most of the air inhaled in step 1 passes through the primary bronchi to the posterior air sacs… In step 2 , the exhalation phase of this first breath, the inhaled air moves from the posterior air sacs into the lungs. There, oxygen and carbon dioxide (CO2) exchange takes place as inhaled air flows through the air-capillary system. The net time that the bird inhales, step 3, the oxygen-depleted air moves from the lungs into the anterior air sacs. The second and final exhalation, step 4, expels CO2-rich air from the anterior air sacs, bronchi, and trachea back into the atmosphere.

15. step 1 step 2 step 3 step 4 Birds Respiratory stages

16. contract contract Exhalation expand expand Inhalation Bird respiration

17. Benefit of 2 respiratory cycles "This series maximizes contact of fresh air with the respiratory surfaces of the lung. Most importantly, a bird replaces nearly all the air in its lungs with each breath. No residual air is left in the lungs during the ventilation cycle of birds, as it is in mammals. By transferring more air and air higher in oxygen content during each breath, birds achieve a more efficient rate of gas exchange than do mammals…

18. Bird-like respiratory systems in dinosaurs A recent analysis showing the presence of a very bird-like pulmonary, or lung, system in predatory dinosaurs provides more evidence of an evolutionary link between dinosaurs and birds. O'Connor and Claessens (2005) make clear the unique pulmonary system of birds, which has fixed lungs and air sacs that penetrate the skeleton, has an older history than previously realized.

19. Rate of breathings in birds Decrease in larger birds A resting 2-gram Humming bird breaths 143 times in a minute. 10-Kg turkey breaths only 7 times in a minute. Birds meet the increased oxygen demand by increasing their ventilation rate to 12-25 times than their normal resting rate.

20. Some related video clips How air moves in and out Furcula ,video learn Avian respiration