NRSC 2100 1st Edition Lecture 16 Vestibular System Functions of Vestibular System Balance equilibrium posture head body eye movement Vestibular Labyrinth Otolith organs gravity and tilt Semicircular canals head rotation Use hair cells like auditory system to detect changes transduction Signaling Mechanism Of Vestibular Sacs Receptive organ macula located horizontally floor in the Utricle and vertically wall in the Saccule when head is upright calcium crystals otoliths move gelatinous cap upon head movement or linear head acceleration embedded stereocilia of hair cells move as with auditory hair cells this or polarization and or rate of action potentials in Scarpa s vestibular neurons Semicircular Canals These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute signal head s rotational acceleration mainly due to inertial resistance of endolymph movement induces bending of Cupula bending of embedded stereocilia of hair cells regulates activity of Scarpa s vestibular neurons Vestibulo Ocular Reflex VOR Function Line of sight fixed on visual target Mechanism Senses rotations of head commands compensatory movement of eyes in opposite direction Connections from semicircular canals to vestibular nucleus to cranial nerve nuclei excite extraocular muscles The Visual World Light Electromagnetic radiation Wavelength frequency amplitude Electromagnetic energy visible light small part Perceived color of light is determined by 3 characteristics properties of electromagnetic energy Hue the spectrum wavelength of light color Brightness height of wavelength amplitude Saturation purity of wavelength Anatomy of The Eye Pupil Opening where light enters the eye Sclera White of the eye Iris Gives color to eyes Cornea Glassy transparent external surface of the eye Optic nerve Bundle of axons from the retina Image Formation on Retina Collection of light by the eye focuses light on retina through cornea Accommodation change of lens shape allows extra focusing power for near objects 9 m Structure of The Retina Direct vertical pathway Ganglion cells Bipolar cells Photoreceptors Structure of The Retina Retinal processing also influenced by lateral connections Horizontal cells Receive input from photoreceptors and project to other photoreceptors and bipolar cells Amacrine cells Receive input from bipolar cells and project to ganglion cells bipolar cells and other amacrine cells Laminar Organization of The Retina Inside out Light passes through ganglion bipolar amacrine and horizontal cells before reaching photoreceptors
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