ANATOMY OF THE OSTRICH
Ostrich, like all ratites, are flightless, although they do possess wings. The ostrich has a large breast plate that covers the thoracic area and protects the heart and liver. There is no keel and thus, no location for the attachment of flight muscles. The heart, lungs and liver are in the thoracic cavity. The ostrich does not have a gall bladder or crop but instead has a glandular stomach called a proventricculus. This stomach empties into a muscular stomach called the ventriculus. The ventriculus contains grit, rocks and other material that helps break down food and allows it to pass into the small intestine. Because the intestine of the ostrich is abnormally long, the amount of time necessary for food to pass thorough it is also long (36 hours). As in most birds, ostrich posses a cloaca which is a common site for excretion by the urinary tract and the digestive tract.
The respiratory system of ostrich as with all birds, consists of lungs, and a system of air sacs that originate in the thorax and extend into the hollow bones. Not all bones are hollow and some, including the lower leg, have a thick cortex. Ostrich can use the air sac system to reduce body heat by panting. The normal respiratory rate of an ostrich is between 7 and 12 breaths/minute.
The reproductive tract of the male ostrich consists of two testicles. The male phallus or penis is located in the ventral cloaca but unlike mammals, does not contain the urethra. The female reproductive tract consists of a single ovary and reproductive tract with a small clitoris located on the ventral cloaca.
Ostrich have two toes (emu and rhea have 3). The larger clawed toe is actually the third digit while the smaller clawless toe is the fourth digit.
The nostrils of ostrich are located forward on the beak, rather than at the base of the beak as in most birds. The trachea or wind pipe is large and located in the lower part of the mouth. The esophagus is above the tracheal opening and extends down the right side of the neck. There is one large jugular vein that runs down the right side of the neck.