RESUMO
Morphometric parameters of olfactory brain components show species-dependent variations. However, the association of these parameters with olfactory function vis-à-vis ecological and evolutionary behaviors is poorly understood. In this study, a morphometric analysis of the olfactory bulb, tract and stria was carried out in three ecologically diverse animals comprising humans (primate), dogs (carnivore) and goats (herbivore) to elucidate differences in morphometry in relation to olfactory function. Using formalin-fixed brains, volumes and linear measurements of the olfactory structures were determined and correlated with those of cerebrum and the whole brain. The volume of the olfactory bulb was greatest in dogs, followed by goats and humans and constituted 0.31 percent, 0.18 percent and 0.01 percent, respectively, of the brain volume. Similarly, the ratio of volume of the bulb, tract and stria to that of brain was 1.95 percent in the dog, 0.77 percent in the goat and 0.03 percent in the human. The width of the bulb was greatest (p< 0.05) in dogs (10.80 +/- 1.64mm) compared to goats (8.25 +/- 0.96mm) and humans (5.50 +/- 0.71mm), and accounted for a hemisphere breadth of 42.91 percent, 29.73 percent and 8.94 percent respectively. Interestingly though, the total length of the olfactory bulb, tract and striae increased in the order of goat (34.5 +/- 1.30mm), human (36.25 +/- 1.70mm) and dog (48.20 +/- 1.92mm), and constituted 21.47 percent, 51.87 percent and 72.30 percent, respectively, of the hemisphere length. These results suggest that the morphometric adaptations of the olfactory components to olfactory function decline from the dog, to goat, to human, and this may be indicative of the varied olfactory functional needs in regard to the ecological diversity of these species.
Los parámetros morfométricos de los componentes del cerebro olfativo presentan variaciones que dependen de las especies. Sin embargo, la asociación de estos parámetros con la función olfativa vis-à-vis los comportamientos ecológicos y evolutivos es poco conocida. En este estudio se llevó a cabo un análisis morfométrico del bulbo, tracto y estría olfatoria en tres animales de diversidad ecológica que abarcan los seres humanos (primates), perros (carnívoros) y cabras (herbívoros) para dilucidar las diferencias en la morfometría en relación con la función olfatoria. El uso de cerebros fijados en formalina, los volúmenes y las medidas lineales de las estructuras olfativas se determinaron y se correlacionaron con el cerebro. El volumen del bulbo olfatorio fue mayor en los perros, seguidos por cabras y seres humanos y constituyeron un 0,31 por ciento, 0,18 por ciento y 0,01 por ciento, respectivamente, del volumen del cerebro. Del mismo modo, la relación entre el volumen del bulbo, vías y estrías al del cerebro fue de 1,95 por ciento en el perro, un 0,77 por ciento en la cabra y 0,03 por ciento en el ser humano. El ancho del bulbo fue mayor (p <0,05) en los perros (10,80 +/- 1.64mm) en comparación con cabras (8,25 +/- 0.96mm) y humanos (5,50 +/- 0.71mm), y representó una total hemisférico de 42,91 por ciento, 29,73 por ciento y 8,94 por ciento respectivamente. Sin embargo, curiosamente la longitud total del bulbo olfatorio, del tracto y estrías aumentaron en la cabra (34,5 +/- 1,30 mm), en humanos (36,25 +/- 1.70mm) y en el perro (48,20 +/- 1,92mm), y constituyeron 21,47 por ciento, 51,87 por ciento y 72,30 por ciento, respectivamente, del largo del hemisferio. Estos resultados sugieren que las adaptaciones morfométricas de los componentes olfativos de la función olfativa se van reduciendo de perro a cabra y al hombre y esto puede ser indicativo de las variadas necesidades funcionales olfativas en lo que respecta a la diversidad ecológica de estas especies.
Assuntos
Cães , Percepção Olfatória/genética , Primatas/anatomia & histologia , Primatas/fisiologia , Primatas/genética , Condutos Olfatórios/anatomia & histologia , Condutos Olfatórios/crescimento & desenvolvimento , Condutos Olfatórios/embriologia , Condutos Olfatórios/fisiologia , Condutos Olfatórios/irrigação sanguínea , Condutos Olfatórios/ultraestrutura , Anatomia Comparada/métodos , Anatomia Veterinária/métodos , Cabras/anatomia & histologia , Cabras/crescimento & desenvolvimento , Cães/anatomia & histologia , Cães/crescimento & desenvolvimento , Cães/fisiologiaRESUMO
The olfactory organ in fish has a distinct localization, a major biological significance, and an important role in fish behavior. One group of Trichomycterus brasiliensis was exposed to two different concentrations of mercuric chloride (0.05 and 0.1 mg HgCl2 liter-1). The surface of the olfactory epithelium was investigated with scanning electron microscopy. Forty individuals were used in this study. The olfactory epithelia were collected after 4, 12, 24, 48, and 96 hr from contaminated and control aquaria. In the experiment with 0.1 mg HgCl2 liter-1 all individuals died within 24 hr with significant damage to the olfactory epithelium. Type 1 ciliated cells were the most evidently altered. With 0.05 mg HgCl2 liter-1 the initial alterations were considerable, but after 96 hr the epithelial surface recovered its initial appearance compared with the control individuals. This recovery is due to the resistance of this species and to the decrease in the Hg2+ concentration in water. Therefore, the alterations observed in this study reveal that inorganic mercury affects the olfactory organs structurally, with evident interference with normal behavior.