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The anatomy of bird's respiratory system, showing the relationships of the trachea, primary and intra-pulmonary bronchi, the dorso- and ventro-bronchi, with the parabronchi running between the two. The posterior and anterior air sacs are also indicated, but not to scale. Inhalation–exhalation cycle in birds.
Cloaca. A cloaca (/ kloʊˈeɪkə / ⓘ kloh-AY-kə), pl.: cloacae (/ kloʊˈeɪsi / kloh-AY-see or / kloʊˈeɪki / kloh-AY-kee), is the rear orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, and a few mammals (monotremes ...
In birds, the bursa of Fabricius (Latin: bursa cloacalis or bursa Fabricii) is the site of hematopoiesis. It is a specialized organ that, as first demonstrated by Bruce Glick and later by Max Dale Cooper and Robert Good, is necessary for B cell (part of the immune system) development in birds. Mammals generally do not have an equivalent organ ...
Pangalloanserae (fowl) Neoaves. Synonyms. Neornithes Gadow, 1883. Birds are a group of warm-blooded vertebrates constituting the class Aves (/ ˈeɪviːz /), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.
The chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles . It develops from an outer fold on the surface of the yolk sac, which lies outside the zona pellucida (in mammals), known as the vitelline membrane in other animals. In insects, it is developed by the follicle cells while the egg is in the ovary. [1]
Syrinx (serial 5) seen just below the crop. The syrinx (from the Greek word "σύριγξ" for pan pipes) is the vocal organ of birds. Located at the base of a bird's trachea, it produces sounds without the vocal folds of mammals. [1] The sound is produced by vibrations of some or all of the membrana tympaniformis (the walls of the syrinx) and ...
Air sac. Air sacs are spaces within an organism where there is the constant presence of air. Among modern animals, birds possess the most air sacs (9–11), with their extinct dinosaurian relatives showing a great increase [clarification needed] in the pneumatization (presence of air) in their bones. [1] Birds use air sacs for respiration as ...
The oviduct in vertebrates is the passageway from an ovary. In human females, this is more usually known as the fallopian tube. The eggs travel along the oviduct. These eggs will either be fertilized by spermatozoa to become a zygote, or will degenerate in the body. Normally, these are paired structures, but in birds and some cartilaginous ...