Let me share with you a difference between parabronchi and alveoli.
| Aspect | Parabronchi | Alveoli |
| Introduction | Parabronchi are present in the lungs of birds | Alveoli are present in the lungs of mammals. |
| Structure | These have tubular structures with a crosscurrent flow of air | Alveoli are small, air sac-like structures at the end of bronchioles. |
| Cartilage | Contains cartilaginous rings to maintain structural integrity. | Absence of cartilage, allowing for greater flexibility in shape. |
| Respiratory mechanism | Unidirectional airflow | Bidirectional airflow |
| Ventilation mechanism | Involves air sacs that allow continuous, one-way airflow through the lungs | Breathing involves the expansion and contraction of the thoracic cavity, leading to inhalation and exhalation |
| Respiratory efficiency | Highly efficient for extracting oxygen from the air | Efficient but less than avian respiratory systems |
| Adaptation for flight | Adapted for the high metabolic demands of flying birds | Not specifically adapted for flight |