Functional significance of the uncinate processes in birds.
J Exp Biol
; 210(Pt 22): 3955-61, 2007 Nov.
Article
en En
| MEDLINE
| ID: mdl-17981863
ABSTRACT
The functional significance of the uncinate processes to the ventilatory mechanics of birds was examined by combining analytical modeling with morphological techniques. A geometric model was derived to determine the function of the uncinate processes and relate their action to morphological differences associated with locomotor specializations. The model demonstrates that uncinates act as levers, which improve the mechanical advantage for the forward rotation of the dorsal ribs and therefore lowering of the sternum during respiration. The length of these processes is functionally important; longer uncinate processes increasing the mechanical advantage of the Mm. appendicocostales muscle during inspiration. Morphological studies of four bird species showed that the uncinate process increased the mechanical advantage by factors of 2-4. Using canonical variate analysis and analysis of variance we then examined the variation in skeletal parameters in birds with different primary modes of locomotion (non-specialists, walking and diving). Birds clustered together in distinct groups, indicating that uncinate length is more similar in birds that have the same functional constraint, i.e. specialization to a locomotor mode. Uncinate processes are short in walking birds, long in diving species and of intermediate length in non-specialist birds. These results demonstrate that differences in the breathing mechanics of birds may be linked to the morphological adaptations of the ribs and rib cage associated with different modes of locomotion.
Buscar en Google
Bases de datos:
MEDLINE
Asunto principal:
Aves
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
J Exp Biol
Año:
2007
Tipo del documento:
Article
País de afiliación:
Reino Unido