Equilibrium By: Hannah Wade, Gabby Ingram, Sydney Little, Bobby Porter, and Hayley Kilburn

Inner Ear anatomy recap Semicircular Canals - three fluid-filled bony channels in the inner ear. Otoliths - involved in sensing gravity and movement. Vestibule – middle part of inner ear, contains saccule and utricle. http://www.carolinaear.com/images/ear_anatomy_4.jpg

Static vs. Dynamic Equilibrium Detects vertical or horizontal acceleration Senses head position, and maintains stability and posture Utricle and saccule within the vestibule Dynamic Detects rotational movement Maintains balance Semicircular canals

Receptors Static Maculae Sense the movement of hair cells to detect movements of the otolithic membrane. Dynamic Crista ampullaris Sense the movement of hair cells to detect movements in the semicircular canal.

Stimulus-Response Pathway Head movement causes otoliths to pool Receptors sense movement of specialized hairs Vestibular branch of vestibulocochlear nerve Motor impulses sent to maintain balance

Stimulus-Response Pathway Continued http://biology4isc.weebly.com/uploads/9/0/8/0/9080078/548887529.jpg?423

Sources The Editors of Encyclopædia Britannica. (n.d.). Inner ear. Retrieved April 21, 2016, from http://www.britannica.com/science/inner-ear Moresea PowerPoint (n.d.). Retrieved April 21, 2016, from http://www.merriam- webster.com/medical/vestibule