Avian Respiration - Anatomy & Physiology

()Map CARDIORESPIRATORY SYSTEM (Map)

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Introduction

The avian respiratory system contains some fundamental changes to the mammalian system.

Avian Nasopharynx and Oropharynx

• The nostrils of the bird, which lead into the nasal cavity, may have a flap of horn to protect them, known as the Operculum.
• The Oral Cavity and the Nasal Cavity of the bird are interconnecting via a slit in the hard palate called the Choana. Birds lack a soft palate.

©Nottingham 2008 Saggital Section of an Avian skull showing the conchae.

• There are Rostral, Middle and Caudal Conchae arising from the lateral wall, filling part of the nasal cavity.
  • Rostral Conchae - Vestibular Region - lined with Stratified Squamous Epithelium
  • Middle Conchae - Respiratory Region - lined with Respiratory Epithelium.
  • Caudal Conchae - Olfactory Region - lined with olfactory epithelium.
• The Infraorbital Sinus is a triangular cavity under the skin, rostroventral to the eye.
• Some marine birds have a Salt Gland (nasal gland) which excretes sodium.

Birds vocalise using a syrinx.

References

• Dyce, K.M., Sack, W.O. and Wensing, C.J.G. (2002) Textbook of Veterinary Anatomy. 3rd ed. Philadelphia: Saunders.