Topics:
Animal Physiology, Animal Refresher
False Statement About Avian Respiration
Which statement is NOT true about avian respiration?
- Site of gaseous exchange in birds is air sacs — Correct Answer
- Paleopulmonic parabronchi is found in all birds
- In fowl, neopulmonic is more developed than paleopulmonic parabronchi
- Tracheal rings are complete
Explanation:
Correct Answer: Site of gaseous exchange in birds is air sacs
This is NOT true. The correct statement is: the site of gaseous exchange in birds is the parabronchi (tertiary bronchi), NOT the air sacs.
Why Air Sacs Are NOT the Site of Gas Exchange
Birds have nine air sacs (two cervical, two anterior thoracic, two posterior thoracic, two abdominal, and one unpaired clavicular). These air sacs are avascular (no blood supply), meaning no gas exchange can occur there. Their function is to act as bellows, moving air through the parabronchi.
Key Facts About Avian Respiration
- Site of gas exchange: Parabronchi (tertiary bronchi)
- Two types of parabronchi: Paleopulmonic (ancient lung) & Neopulmonic (new lung)
- Paleopulmonic: Found in ALL birds; airflow is unidirectional
- Neopulmonic: Airflow is bidirectional; absent in penguin & emu; more developed in fowl & songbirds
- Diaphragm: Absent in birds
- Both inspiration and expiration are active processes in birds (unlike mammals where expiration is passive)
- Birds have a larynx but it is not used for sound; instead the syrinx is the voice box of birds
- Avian respiratory system is more efficient than mammalian
Why Other Statements Are TRUE
- Paleopulmonic parabronchi is found in all birds — TRUE
- In fowl & songbirds, neopulmonic is more developed — TRUE
- Tracheal rings are complete in birds (unlike mammals where they are C-shaped) — TRUE
