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psyb51 ch.15
Spatial Orientation
Question | Answer |
---|---|
Vestibular system | set of 5 organs--- 3 semicircular canals & 2 otolith organs--- located in each inner ear that sense head motion and head orientation w/respect to gravity. (Vestibular labyrinth) |
Spatial orientation | sense comprised of 3 interacting sensory modalities: our senses of linear motion, angular motion, & tilt |
Otolith organs | mechanical structures in the vestibular system that sense both linear acceleration & gravity |
Semicircular canals | 3 toroidal tubes in the vestibular system that sense angular motion |
Amplitude | magnitude of displacement (increase or decrease) of a head movement s/a angular velocity, linear acceleration, & tilt. |
Sense of angular motion | spatial orientation modality that senses motion resulting from rotation |
Sense of linear motion | spatial orientation modality that senses translation |
Sense of tilt | spatial orientation modality that senses head inclination in respect to gravity |
Hair cells | cells that support the stereocilia that transduce mechanical movement in the vestibular labyrinth into neural activity sent to the brain stem |
Mechanoreceptors | sensory receptors that are responsive to mechanical stimulation (pressure, vibration, movement) |
Receptor potential | change in voltage of sensory receptor cells--- hair cells for the vestibular system--- in response to stimulation |
Utricle | 1 of the 2 otolith organs. Saclike structure that contains the utricular macula |
Saccule | 1 of the 2 otolith organs. Saclike structure that contains the saccular macula |
Maculae | specialized detectors of linear acceleration & gravity found in each otolith organ |
Otoconia | tiny calcium carbonate stones in the ear that provide inertial mass for the otolith organs, enabling them to sense gravity & linear acceleration |
Vection | illusory sense of self motion produced when you are not moving |
Vestibular system; set of specialized sense organs located in the inner ear right next to the cochlea | Organs sense motion of the head, as well as the orientation of gravity & make predominant contribution to sense of tilt and sense of self-motion. Contributes to clear vision & maintain balance when we move |
Vestibular sensation | dizziness, spatial disorientation, imbalance, blurred vision, &/or illusory self-motion when problems arise |
Sensing linear motion, angular motion, & tilt (3 modalities) requires | diff. receptors &/or diff. stimulation energy as vision and audition do |
Vestibular transduces 3 stimulation energies | gravity, angular acceleration, & linear acceleration |
Signals frm the otolith organs are ambiguous b/c | they transduce both linear acceleration & relative orientation of gravity into a neural signal (reliance on the brain and not the otolith organs to tell the diff. b/w gravity and linear acceleration) |
Direction | perceived linear motion might be forward, up, & to the left |
Amplitude | speed of our perceived motion can be large or small (see definition) |
Angular motion eg | close eyes and nod head as if saying no (left to right) |
Relatively pure linear motion | cannot be done passively but riding in a car or train. Eg. passenger in a car, perceive motion as car reverses (backward linear motion), cessation of translation as car stops, and then forward translation as car moves forward |
Sense of tilt eg. close your eyes and nod as if saying yes (up and down). Pitch head forward & hold it there for few seconds; then pitch head backwards & hold it there | |
Direction | x-axis: points forward; y-axis points out to the left ear; & z-axis always points outs the top of the head |
Roll | directional quality; |
Pitch | directional quality |
Yaw | directional quality |
Vestibular labyrinth | organs respond primarily to head motion both linear & angular & head tilt in respect to gravity |
Each ear | has a separate vestibular system and five organs in each |
Receptor potential | changes in hair cell voltage---are proportional to the bending of the hair cell bundles & control the rate @ which hair cells release neurotransmitter to afferent neurons |
Rate of Aps transmitted (in voltage change of hair cells) | by afferent neurons increases or decreases following the hair cell receptor potential |
Semicircular canals | are maximally sensitive to rotations in in diff. planes yielding part of the direction coding for head rotation |