Abstract:
Herbst corpuscles are widely distributed throughout the oropharynx of
the ostrich and emu in contrast to the general situation in birds. Knowledge
of the comparative distribution of Herbst corpuscles in the oropharynx
of these two commercially important ratite species may assist in a
better understanding of their feeding habits. Tissue sections representing
all parts of the oropharynx of five ostrich and five emu heads collected
after slaughter were prepared for light microscopy, the Herbst corpuscles
counted, and the relative percentage of corpuscles calculated for defined
anatomical regions. Herbst corpuscles were more widespread in the oropharynx
of the emu (where they were additionally found in the tongue and
laryngeal mound) than in the ostrich but were absent from the pharyngeal
folds in both species. The results further indicated that Herbst corpuscles
were strategically located to aid in the handling and transport of food. In
this context, the high concentration of Herbst corpuscles in the prominent
median palatine and ventral ridges in the ostrich denote these structures
as sensory organs, namely the palatal and interramal organs. The presence
of these sensory organs, coupled with the higher relative percentage of
Herbst corpuscles located on the rostral oropharyngeal floor, indicate that
the part of the oropharynx caudal to the mandibular and maxillary rostra
forms an important sensory region in the ostrich. Additionally, speciesspecific
concentrations of Herbst corpuscles within the oropharynx were
identified which appear to assist in the accurate positioning of the tongue
and laryngeal mound for cleaning the choana (internal nares) after swallowing.
