Avian respiratory system

Avian respiratory system

Delivers oxygen from the air to the tissues and removes carbon dioxide.

thermoregulation

How Avian respiratory system differs from mammals?

Presence of air sacs and air spaces

Lungs structure

Unidirectional flow

Air sacs

Inconspicuous, but integral, part of the avian respiratory system…

Air sacs are thin-walled structures…

Extend into the body cavity and into the wing and leg bones…

Air sacs benefits

Unidirectional flow of air

Delivers huge quantity of O2

Remove lethal body heat

Protect internal delicate organs

Interclavicular sac is essential for vocal sound production

unidirectional flow of air

Air sacs

Mostly birds have 9

In weavers 6

7 in loons and turkeys

12 in shorebirds and strokes

Paired cervical air sacsStrutting sage grouse Frigate birds

Birds inhalation

Birds inhale by lowering the sternum, which enlarges the chest cavity and expands the air sacs.

Contraction of the sternum and ribs compresses the air sacs, pushes fresh air from them through the lungs, and exhales the air

Howdobirdlungswo-Download-From-YTPak.com.3gp

Birds respiration

Parabronchi

Cross current exchange

blood flow at 90o to air flow

Parabronchus

Unidirectionalair flow

Pul. artery

Pul. vein

Allows oxygenated blood that leaves the lung to have a higher oxygen tension than the oxygen partial pressure in exhaled air

Respiratory cycles

"Inhaled air proceeds through two respiratory cycles that, together, consist of four steps.

Most of the air inhaled in step 1 passes through the primary bronchi to the posterior air sacs…

In step 2, the exhalation phase of this first breath, the inhaled air moves from the posterior air sacs into the lungs. There, oxygen and carbon dioxide (CO2) exchange takes place as inhaled air flows through the air-capillary system. The net time that the bird inhales, step 3, the oxygen-depleted air moves from the lungs into the anterior air sacs. The second and final exhalation,

step 4, expels CO2-rich air from the anterior air sacs, bronchi, and trachea back into the atmosphere.

step 1step 2

step 3 step 4

Birds Respiratory stages

contract

contract

Exhalation expand

expand

Inhalation

Bird respiration

Benefit of 2 respiratory cycles

"This series maximizes contact of fresh air with the respiratory surfaces of the lung.

Most importantly, a bird replaces nearly all the air in its lungs with each breath. No residual air is left in the lungs during the ventilation cycle of birds, as it is in mammals.

By transferring more air and air higher in oxygen content during each breath, birds achieve a more efficient rate of gas exchange than do mammals…

Bird-like respiratory systems in dinosaurs A recent analysis showing the presence of a

very bird-like pulmonary, or lung, system in predatory dinosaurs provides more evidence of an evolutionary link between dinosaurs and birds.

O'Connor and Claessens (2005) make clear the unique pulmonary system of birds, which has fixed lungs and air sacs that penetrate the skeleton, has an older history than previously realized.

Rate of breathings in birds Decrease in larger birds

A resting 2-gram Humming bird breaths 143 times in a minute.

10-Kg turkey breaths only 7 times in a minute.

Birds meet the increased oxygen demand by increasing their ventilation rate to 12-25 times than their normal resting rate.

Some related video clips

How air moves in and out

Furcula ,video learn

Avian respiration

Howdobirdlungswo-Download-From-YTPak.com.3gp

Furcula-VideoLear-Download-From-YTPak.com.mp4

TheAvianRespirator-Download-From-YTPak.com.3gp