Presentation on theme: "Avian Anatomy. Skeletal System Skeleton is very unique and specially adapted for flight Very lightweight; yet strong Most of the long bones are hollow."— Presentation transcript:
Skeletal System Skeleton is very unique and specially adapted for flight Very lightweight; yet strong Most of the long bones are hollow but reinforced through a honeycombed structure Flying species have a large keel Keel - place on the sternum that the flight muscles attach
Respiratory System Different from mammals in many ways. Bird respiration is much more efficient. Birds do not have a diaphragm. In mammals this moves up and down to increase and decrease the chest cavity. Birds push the sternum in and out to the same effect Hummingbird breathes 143 times per minute while a turkey breathes 7 times per minute Rate increases during flight.
Breathing Cycle Bird lungs are very compact and take up much less space than mammal lungs The air enters through the nostrils, down the trachea and into the lungs and air sacs Thin-walled air sacs extend through the body cavity and even into the bones Birds can keep a continuous flow of air through the lungs.
Digestion Birds has special digestive tracts because they do not chew their food First the food travels down the esophagus and into the crop. The crop is an expanded section of the esophagus. It is used as a holding tank for food before it can enter the proventriculus The proventriculus produces acid and adds enzymes which aid in breaking down the food
The gizzard helps grind food like seeds The gizzard is highly keratinized to make the surface rough Turkey gizzard can crush walnuts and steel needles Food then passes through the intestinal tract, where nutrients are absorbed Waste is expelled through the cloaca, or vent.
Reproductive Tract The reproductive organs shrink whenever birds are not in breeding season This decreases their weight Males have 2 testes and females have 1 ovary Eggs production: The ovum is fertilized and passes through a long tube called the oviduct Each section of the oviduct adds a different part to the egg, just like an assembly line
The egg assembly In the infundibulum the egg stays 20 minutes before going to the magnum where the egg white is added Next the egg goes to the isthmus, where inner and outer membranes are formed This process takes about 1 hour In the uterus the shell and all pigments are added (20 hrs) The egg then passes out the cloaca