HMB200H1 Chapter Notes - Chapter 11: Ventral Posterior Nucleus, Vestibulospinal Tract, Tinnitus
Document Summary
Pinna visible portion of ear: sound localization. Auditory canal entrance to inner ear. Oval window receives eardrum movements from ossicles. Sound wave moves eardrum: eardrum moves ossicles, ossicles move oval window membrane, oval window motion moves cochlea fluid, chochlea fluid movement causes response in sensory neurons. Auditory receptors in cochlea breain stem neurons medial geniculate nucleus 0 auditory cortex (a1: malleus (hammer, incus (anvil) Footplate flat bottom of stapes: like piston at oval window, transmits sound vibrations to fluids of cochlea in inner ear. Attenuation reflex: to adopt ear to lound sounds, protect from damage (50 100 msec delay, tensor tympani muscle (to malleus) and strapedius muscle (to stapes) contract and stiffen ossicles, sound diminished. Scala vestibule reissner"s membrane scala media basilar membrane (on top of which is tectorial membrane and organ of corti) scala tympani. Perilymph like cerebrospinal fluid: low k+, high na, in tympani and vestibule. Endolympth like intracellular fluid: low na+, high k, in media.
