Effect of fluid forcing on vestibular hair bundles.
A dynamic 3-D hair bundle model including inertia and viscous fluid drag effects based on the finite element method is presented. Six structural components are used to construct the hair bundle--kinocilium, stereocilia, upper lateral links, shaft links, tip links, and kinocilial links. Fluid drag is distributed on the surface of cilia columns. Bundle mechanics are analyzed under two distinct loading conditions: (1) drag caused by the shear flow of the surrounding endolymph fluid (fluid-forced), (2) a single force applied to the tip of the kinocilium (point-forced). A striolar and a medial extrastriolar vestibular hair cell from the utricle of a turtle are simulated. The striolar cell bundle shows a clear difference in tip link tension profile between fluid-forced and point-forced cases. When the striolar cell is fluid forced, it shows more evenly distributed tip link tensions and is far more sensitive, responding like an on/off switch. The extrastriolar cell does not show noticeable differences between the forcing types. For both forcing conditions, the extrastriolar cell responds serially--the nearest tip links to the kinocilium get tensed first, then the tension propagates to the farther tip links.
Nam
J-H
JH
Department of Engineering Science and Mechanics, and School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Cotton
J R
JR
Grant
J W
JW
D000465:Algorithms; D000818:Animals; D002923:Cilia / Q000502:physiology*; D003198:Computer Simulation; D020342:Finite Element Analysis; D018495:Fluid Shifts; D006198:Hair Cells, Auditory / Q000502:physiology*; D021621:Imaging, Three-Dimensional; D007761:Labyrinthine Fluids; D008432:Mathematical Computing; D008954:Models, Biological; D009068:Movement / Q000502:physiology; D014426:Turtles; D014722:Vestibule, Labyrinth / Q000166:cytology / Q000502:physiology*; D014783:Viscosity