Birds

Birds

1. Respiratory system: There is no diaphragm separating the thorax and the abdomen

   • the lungs and rigid and do not inflate with air
     • airs inflates airs sacks that are found around the bod caity and in the major bones (Femur, humerus)
       • Air enters the lungs and either enters the parabronchi when gas exchange occurs and then inflate the cranial airs sacs or on expiration the air in the cranial air sacs in breathed out and the air in the caudal air sacs in pushed to the parabronchi for gas exchange and then inflates the cranial air sacs. Air passes through the lungs twice.

2. Pneumatic bones: they are filled with air sacs that are connected to the respiratory system. Lighten the skeleton.

   • Keel: the sternum is extended to form an area for large muscles attachment for flight muscles. pectorals - adducter musclse - powerful push down.

3. Integument: Feather types

   • Flight feathers: Attaches to digits and metacarpal and ulna
   • Contour feather: cover rest of wing and body
   • Down feathers: Insulates
   • Filoplumes: sensory feathers - long feather with tassel at the end

4. Birds lay eggs, - as the eggs goes through the oviduct the shell membrane lays the egg shell.

   • Vagina opens in to cloaca
     • Cloaca- urine and faeces combined leads to vent

5. Gizzard - Muscular organ where mechanical digestion occurs. food is ground up by powerful contractions, mixed with digestive juices and grit.