Macula of utricle - Wikipedia Macula of utricle Macula of utricle illustration of otolith organs showing detail of utricle, otoconia, endolymph, cupula, macula, hair cell filaments, and saccular nerve Details Identifiers Latin macula utriculi Dorlands / Elsevier m_01 / 12509297 TA A15. 3.03. 083 FMA 74960 Anatomical terminology ( edit on Wikidata ) The macula of the utricle, or utricular macula is the region of the utricle that receives the utricular filaments of the vestibulocochlear nerve. The portion of the utricle that forms the macula forms a sort of pouch or cul - de-sac, with a thickened floor and anterior wall. The macula of utricle allows a person to perceive changes in longitudinal acceleration ( in horizontal directions only ). Contents 1 Layers 2 Signals 3 References 4 External links Layers The macula consists of three layers. The bottom layer is made of sensory hair cells which are embedded in bottom of a gelatinous layer. Each hair cell has between 40 and 70 steriocilia and a kinocilium, which lies in the middle of the steriocilia and is the most important receptor. On top of this layer lie calcium carbonate crystals called statoconia or otoliths. The otoliths are relatively heavy, providing weight to the membrane as well as inertia. This allows for a greater sense of gravity and motion. The gelatinous layer and the statoconia together are referred to as the otolithic membrane, where the tips of the stereocilia and kinocilium are embedded. When the head is tilted such that gravity pulls on the statoconia the gelatinous layer is pulled in the same direction also causing the sensory hairs to bend. Signals Unbent and at rest hairs in the macula have a base rate of depolarization of 90 - 100 action potentials a second. The brain suppresses this, and we ignore it and know that our body is stabilized. If the head moves or the body accelerates or decelerates, then bending occurs. Depending on the direction of bending, the hair cells will either be excited or inhibited resulting in either an increase or decrease in firing frequency of the hair cells. The macula is also sensitive to linear acceleration as the inertia possessed by the statoconia can also shift the gelatinous layer during increases and decreases in linear velocity. References This article incorporates text in the public domain from the 20th edition of Gray 's Anatomy ( 1918 ) External links http://www.neurophys.wisc.edu/h&b/textbook/chap-7.html#Obj2 Anatomy of hearing and balance Outer ear Auricle helix antihelix tragus antitragus intertragic notch earlobe Ear canal Auricular muscles Eardrum umbo pars flaccida Middle ear Tympanic cavity Medial structures oval window round window secondary tympanic membrane prominence of facial canal promontory of tympanic cavity Posterior structures mastoid cells aditus to mastoid antrum pyramidal eminence Ossicles Malleus superior ligament lateral ligament anterior ligament Incus superior ligament posterior ligament Stapes annular ligament Muscles stapedius tensor tympani Auditory tube / Eustachian tube Torus tubarius Inner ear / ( membranous labyrinth, bony labyrinth ) Auditory system / Cochlear labyrinth General cochlea Vestibular duct Helicotrema Tympanic duct Modiolus Cochlear cupula Perilymphatic space Perilymph Cochlear aqueduct Cochlear duct / scala media Reissner 's / vestibular membrane Basilar membrane Reticular membrane Endolymph Stria vascularis Spiral ligament Organ of Corti stereocilia tip links Tectorial membrane Sulcus spiralis externus internus Spiral limbus Cells Claudius cell Boettcher cell Vestibular system / Vestibular labyrinth Vestibule Utricle macula Saccule macula Kinocilium Otolith Vestibular aqueduct endolymphatic duct endolymphatic sac Ductus reuniens Semicircular canals Superior semicircular canal Posterior semicircular canal Horizontal semicircular canal Ampullary cupula Ampullae crista ampullaris This anatomy article is a stub. You can help Wikipedia by expanding it. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Macula_of_utricle&oldid=784821621 '' Categories : Wikipedia articles incorporating text from the 20th edition of Gray 's Anatomy ( 1918 ) Vestibular system Anatomy stubs Hidden categories : Medicine infobox template using GraySubject or GrayPage Medicine infobox template using Dorlands parameter All stub articles Talk Contents About Wikipedia Català Edit links This page was last edited on 10 June 2017, at 08 : 16. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: the macula is the sensory organ that responds to
Answer: changes in longitudinal acceleration (in horizontal directions only)