AVIAN PHYSIOLOGY

Meeting the demands of flight

FlightMost E-demanding type of locomotion (E/T)

Most efficient type of locomotion (E/D)

- An integrated physiology- Solutions and costs associated w/ meetings the demands of flight- Comparative physiology - largely with mammals- Basic

FlightMost E-demanding type of locomotion (E/T)

Most efficient type of locomotion (E/D)

Hi metabolismRespiration

Circulation

Excretory System

Flight

Hi metabolismRespiration

Circulation

- BMR can increase (2-25)- Glucose levels 2 mammalian- Mean body Temp ~40°

- nerve impulse trans. - spd/strength muscle contrac.

Flight

Hi metabolismRespiration

Circulation

- BMR can increase (2-25)- Glucose levels 2 mammalian- Mean body Temp ~40°

- nerve impulse trans. - spd/strength muscle contrac.

In flight 2-25 BMR

CO2 in blood; ~8 pH Heat

Flight

Hi metabolismRespiration

Circulation

- BMR can increase (2-25)- Glucose levels 2 mammalian- Mean body Temp ~40°

- nerve impulse trans. - spd/strength muscle contrac.

In flight 2-25 BMR

CO2 in blood; ~8 pH Heat

HOW??

Evaporative water loss N turnover/loss

Flight

Hi metabolismRespiration

Circulation

- BMR can increase (2-25)- Glucose levels 2 mammalian- Mean body Temp ~40°

- nerve impulse trans. - spd/strength muscle contrac.

In flight 2-25 BMR

CO2 in blood; ~8 pH Heat

- Intake of metabolic water: 1 g fat 1.04 ml H2OVerdin (9-10g): replaces 4.5g ml H2O/dy 100% H2O & 50% body mass

- Hyperthermia: higher body temp reduces loss of H2O

Evaporative water loss N turnover/loss

Flight

Hi metabolismRespiration

Circulation

- BMR can increase (2-25)- Glucose levels 2 mammalian- Mean body Temp ~40°

- nerve impulse trans. - spd/strength muscle contrac.

In flight 2-25 BMR

CO2 in blood; ~8 pH Heat

- Intake of metabolic water: 1 g fat 1.04g ml H2OVerdin (9-10g): replaces 4.5g ml H2O/dy 100% H2O & 50% body mass

- Hyperthermia: higher body temp reduces loss of H2O

Excrete N as Uric Acid crystals not Urea[0.5 ml H2O to flush 370 mg N as Uric Acidvs. 20 ml H2O to flush the same as Urea]

Evaporative water loss N turnover/loss

Excretory System

Urea

Uric acid

Flight

Hi metabolismRespiration

Extremely Efficient - Directional - 2 inhales/exhales per cycle- Complete refilling- unidirectional airflow (thru the lungs not into and out of lungs) - Efficiency reduces water loss through respiration

Air Post Air sacs lungs Ant Air sacs Out

(Inhale) (Inhale)(exhale) (exhale)

Excretion

No diaphragm, but spring-likeaction by the of the furula assists and of the chest cavity

Increased Efficiency

Compared to mammals:

- Air breathed into lungs, mixes w/ stale air in alveoli, then out - 1 breath per cycle - Bi-directional- Refilling is incomplete- 20% or more is dead space

1 breaths birds: 3-4 in mammals

Respiration

Circulation

Flight

Hi metabolism

- 4-chambered heart (compared to single ventricle heart of Reptiles)- Dual circulation (separate pulmonary/systemic)

- Avian hearts 50-100% (wt.) larger in birds- More mitochondria, muscle fibers - pulmonary performance: 100-200 ml blood/kg more efficient - 14% of blood shunted to legs for heat loss

As in mammals Excretion

Respiration

Circulation

Flight

Hi metabolism

- 4-chambered heart- Dual circulation (separate pulmonary/systemic

- Avian hearts 50-100% (wt.) larger in birds- More mitochondria, muscle fibers - pulmonary performance: 100-200 ml blood/kg more efficient- 14% of blood shunted to legs for heat loss

Gas exchangeHb efficiency: Duck [O2] gradient between venous and arterial ~ 60%

Humans ‘’ ‘’ ‘’ ‘‘ ‘’ ~ 27%

Temperature CO2 } help dissociation

Excretion

Other sorts of changes:

Digestive: • lack teeth but use a gizzard for grinding (stones) • Cloaca (Dig, Rep, Uro)

Urogenital: • All egg laying• Single functional ovary/oviduct (left), most males lack phallus• No bladder

Misc:• Females are heterogametic sex• RBC nucleated• Embryo nutrition is yolk-derived