ANFS 240 Avian Respiratory (Exam 3)

Avian Respiratory System

• Very different from the mammalian respiratory system

• Important to understand because poultry kept in production systems are particularly susceptible to respiratory diseases

• Breathe very differently than mammals

Nostrils (nares)

At the base of the beak
• Opening to the nasal cavity
• Septum on median plane

Conchae

Contained by nasal cavity
• Important for olfaction (sense of smell), filtering out pollutants, and thermoregulation, much like the mammalian conchae

Nasal gland (“salt gland”)

Within the nasal cavity
• Secretes salt in marine species, allowing them to drink seawater

Larynx

Made of only arytenoid and cricoid cartilage
• Arytenoid cartilage closes the glottis – no epiglottis

Trachea

• Tightly stacked, overlapping, complete cartilaginous rings

  • Mostly on the right side, close to the esophagus which runs on the right

  • Longer than the actual neck in long-necked species (swans, etc) & loops around within a specialized area of the sternum

• Trachea bifurcates into two bronchi, like mammals

Syrinx

• No vocal folds in the larynx – all vocalization occurs in the Syrinx

• Terminal part of the trachea + first parts of the primary bronchi

• Initial parts of the bronchi are membranous (no cartilage), and will make sound when they vibrate

• Certain species, like songbirds, have more intricate syringeal musculature

• Parrots actually have very few syringeal muscles, compared to songbirds

• Common location for foreign body obstruction
  

Avian Bronchi and Lungs

• Lungs: Very small, not lobed

  • Do not expand like mammalian lungs

  • Exist in the craniodorsal part of the body cavity (not lateral) & are loosely attached to the body wall (not free)

• Primary bronchi give rise to 40-50 secondary bronchi

Parabronchi

• Secondary bronchi (3,4,5) give rise to 400-500 parabronchi (6)

• Loops that connect the bronchi

• Medioventral/mediodorsal region – paleopulmonic region

  • Tightly packed parabronchi loops

• Lateroventral/laterodorsal region – neopulmonic region

  • Less regular arrangement of loops

Paleopulmonic Region

• Medioventral/mediodorsal region

  • Tightly packed parabronchi loops

Neopulmonic region

• Lateroventral/laterodorsal region

  • Less regular arrangement of loops