Modelling of the static and dynamic mechanical properties of human otoliths [Elektronische Ressource] / vorgelegt von Rudolf Jäger

Modelling of the static and dynamicmechanical properties of humanotolithsDISSERTATIONzur Erlangung des Grades eines Doktorsder Naturwissenschaftender Fakult¨at fu¨r Mathematik und Physikder Eberhard-Karls-Universit¨at zu Tu¨bingenvorgelegt vonRudolf Jager¨aus Ellwangen2003Tag der mu¨ndlichen Pru¨fung: 23.07.2003Dekan: Prof. Dr. Herbert Muther¨1. Berichterstatter: Prof. Dr. Hanns Ruder/PD. Dr. Thomas Haslwanter2. Berichterstatter: Prof. Dr. -Ing. Andrew H. ClarkeFluctuat nec mergiturMotto of the city of ParisAbstractThe aim of this study is a numerical investigation of the static and dynamic prop-erties of the otoliths. The otoliths are a part of the vestibular system, located inthe inner ears. They sense accelerations of the head. In the static case, informationretrieved from them indicates the orientation of the head with respect to gravity.Under dynamic conditions, they provide information about the current directionand magnitude of head acceleration. Two important parts of the otoliths can bedistinguished with respect to their function in the sensory apparatus, the otolithmembrane and macula. The otolith membrane, a flat, layered filament structure isdeformed by head accelerations. Though materials within the inner ear have simi-lar densities, this membrane is subject to external accelerations because it containshigher density crystals, known as otoconia. The otolith macula contains hair cells,the sensory units of the otoliths.