phystut5 - TheVestibularSystem It is necessary for...

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The Vestibular System  It is necessary for providing information about the position and movement of the head in space. How many ways can the head move in space? 3 rotational 3 translational (linear acceleration) Yaw X -axis Pitch Y-axis Role Z-axis
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Vestibular Apparatus  The vestibular apparatus is the collective term for two distinct vestibular organs. Semicircular Canals Otolith Organs 3 canals that are angled at 90 degrees of each other. Each provides information about the rotation of the head in space. Provide information about translational (linear) movement and the position relative to gravity. There are two separate otolith organs. 1.Saccule 2. Utricle There is a specialized region in each of these organs which transduce motion, these are? Hair Cells
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 Rotational Balance:  Semicircular Canals  The semicircular canals are filled with a fluid that is produced by neighbouring epithelial cells, it is known as the endolymph . The ampulla is the part of the semicircular canal where transduction takes Place. The ampullae contain hair cells, very similar to those found in the cochlea, this is how transduction takes place. Ampulla
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Ampullae: Transduction  The hair cells within the ampulla transduce the signal from the fluid into AP’s that are then sent to the CNS. The hair cells project into the cupula, a gelatinous substance that seals the inner diameter of each semicircular canal. Fluid waves that are generated by rotation of the head, push against the cupula. This distortion of the cupula will bend the hair cells, the direction of bending depends on which way the head is being moved.
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Ampullae: Transduction  Which way does the endolymph move with respect to head rotation? This is because there is of interia. The bending of the hair cells will cause them to either depolarize or hyperpolarize. This signals are then sent to the CNS via the vestibular nerve fiber. OPPOSITE Nerve fiber to CNS
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The Otolith Organs  There are two otolith organs Utricle Saccule The portion of the otolith organ where transduction takes place is? Macula ampulla
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The Macula (Macaulae)  The hair cells in the macaulae project into a gelatinous membrane called the otolithic membrane. On top of this membrane are otoconia . (stones made of calcium carbonate). These stones add inertia . This allows the membrane to detect linear or translational movement.
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Otolith Organs: Transduction  Bending of the head or translational movement (linear acceleration) causes the otolithic membrane to “slide”. The two forces that cause this are? This causes a bending of the embedded
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This note was uploaded on 02/27/2010 for the course PHYSIOL 2210 taught by Professor Betts during the Spring '10 term at UWO.

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phystut5 - TheVestibularSystem It is necessary for...

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