Gas Exchange - Birds Flashcards
What is the structure of the respiratory system in birds?
A pair of rigid lungs and extendable anterior and posterior air sacs
What are the 3 types of bronchi in birds?
Ventrobronchi, Dorsobronchi, and parabronchi
Which air sac does inhaled air go to first?
Posterior
Where does the air go after the posterior air sacs?
Through the parabronchi and into the anterior air sacs
Where do the posterior air sacs pull air from? Is it fresh or depleted?
Trachea and bronchial tubes. Fresh air
Where do the anterior air sacs pull air from? Is it fresh or depleted?
The parabronchi. Depleted air
Where is the site of gas exchange in birds?
The parabronchi
What is the respiratory cycle in birds?
- Chest expands, fresh air goes through the bronchi into the posterior air sacs
- Chest compresses, fresh air is pushed from the posterior air sacs into the parabronchi
- Chest expands, stale air flows from the parabronchi into the anterior air sacs
- Chest compresses, stale air flows from the anterior air sacs out
Which steps in the respiratory cycle are occurring simultaneously?
1 and 3, and 2 and 4
What is happening during step 1 of the respiratory cycle of birds?
Chest expands, fresh air flows from the trachea into the posterior air sacs
What is happening during step 2 of the respiratory cycle of birds?
Chest compresses, forces air from the posterior air sacs into the parabronchi
What is happening during step 3 of the respiratory cycle of birds?
Chest expands, air flows from parabronchi to anterior air sacs
What is happening during step 4 of the respiratory cycle of birds?
Chest compresses, forces air from the anterior air sacs out
What type of ventilation is seen in birds?
Unidirectional cross current
Why do birds use unidirectional cross-current ventilation?
Flight uses up a lot of oxygen, and cross-current ventilation allows pressure of oxygen in the blood to always be higher than the pressure of the ambient air, so they always have enough oxygen