Cat hair receptors were studied to determine whether they could be distinguished by the following receptive field characteristics: thickness of innervated guard hairs, distance between innervated follicles and receptive field size. Initially the receptors were classified as G1, GI, G2 or D on the basis of their velocity requirements for excitation, their degree of linear directionality, their vibrational sensitivity, and whether they were activated by movement of down hairs. It was found that the thickest guard hairs on the posterior aspect of a cat's hindleg were usually 4-5 times thicker than the thinnest guard hairs from the same area and that G1, GI and G2 neurons innervated the full range of guard hair thicknesses available. Although there was a tendency for thicker guard hairs to be more heavily innervated, none of the neurons studied innervated thick guard hairs exclusively. While movement of the down hair and most guard hairs within D-mechanoreceptive fields easily evoked activity, a few guard hairs were regularly found for which mechanical displacement did not elicit a discharge even though they were well within the receptive field. Receptive field sizes and nearest neighbor distances between innervated follicles were smaller for D than for G1, GI and G2 receptors and greater for G1 than GI and G2 receptors.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2016-12-20T10:33:59Z No. of bitstreams: 2 Tese - Gisele Aparecida Felix - 2016.pdf: 1558360 bytes, checksum: 761cc39345caea8787f3f1e6a9816a8c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-12-27T12:47:48Z (GMT) No. of bitstreams: 2 Tese - Gisele Aparecida Felix - 2016.pdf: 1558360 bytes, checksum: 761cc39345caea8787f3f1e6a9816a8c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-12-27T12:47:48Z (GMT). No. of bitstreams: 2 Tese - Gisele Aparecida Felix - 2016.pdf: 1558360 bytes, checksum: 761cc39345caea8787f3f1e6a9816a8c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-06-24 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Outro / Trichology is a method to analyze micro-structural patterns of scarf-skin scales arrangements and medullary cells found in mammals guard hair. The present study was conducted to identify Caracu, Curraleiro Pé-Duro, Pantaneiro and Nellore bovine breeds by trichological morphology and morphometry, as well as validate the technique compared with genetic characterization. This study was presented in chapters. First, a review on trichology application on mammal species and breeds identification with basic concepts necessary for understanding trichology analysis and its applications. The second chapter was composed by characterization of guard hair of Caracu, Curraleiro Pé-Duro and Pantaneiro (Bos taurus taurus) and of Nellore (Bos taurus indicus), Brazilian bovine breeds, through trichology analysis, to assess the possibility of using this technique as a racial marker. Morphological and morphometric descriptions were held by 160 cattle (40 animals/breeds). Sub-samples of each bovine were made until quality slides were obtained. Morphology was determined through dichotomous keys and measures were carried out in the cuticle scale and in the hair shield matrix. Results indicated that trichology and genetic evaluation were similar in the point of view of classification of individuals within racial groups. Therefore, the technique can be considered useful as a marker for bovine breeds. / A tricologia é um método que permite analisar os padrões microestruturais de arranjos de escamas cuticulares e células medulares encontradas em pelos guarda de mamíferos. O presente estudo foi conduzido com o objetivo de identificar as raças bovinas Caracu, Curraleiro Pé-Duro, Pantaneiro e Nelore por meio da morfologia e morfometria tricológica, bem como validar a técnica comparando com resultados da caracterização genética. Esse estudo foi apresentado em forma de capítulos, com uma revisão de literatura sobre a aplicação da tricologia na identificação de espécies de mamíferos e de raças de interesse zootécnico, onde foram disponibilizadas informações sobre os conceitos básicos necessários ao entendimento da análise tricológica e suas aplicações. O capítulo seguinte foi composto pela caracterização de pelos guarda das raças bovinas Caracu, Curraleiro Pé-Duro e Pantaneiro (Bos taurus taurus) e da raça Nelore (Bos taurus indicus), por meio de análise tricológica, a fim de avaliar a possibilidade de uso desta técnica como marcador racial. Realizaram-se descrições morfológicas e morfométricas dos pelos de 160 bovinos (40 animais/raça). De cada bovino foram feitas subamostras de pelos até serem obtidas lâminas de qualidade. A morfologia foi determinada por meio de chave dicotômica e as medidas foram realizadas na escama cuticular e na medula e os resultados dessa metodologia foram comparados à caracterização genética dos animais amostrados. Os resultados indicaram que a tricologia e a avaliação genética foram similares no ponto de vista de classificação dos indivíduos dentro dos grupos raciais. Portanto, a técnica pode ser considerada útil como marcador racial para raças bovinas.