425528
Description
Mind Map by natalieclark29, updated more than 1 year ago
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Created by natalieclark29
about 12 years ago
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Vestibular System
- What is it?
- Senses spatial orientation
- Three things
- Translational motion
- Rotational acceleration
- Tilt
- Translational motion
- Senses spatial orientation
- Anatomy
- Inner ear
- cavity in the temporal bone near the cochlea
- Three semi-circular canals
- Anterior
- Posterior
- Horizontal
- Anterior
- otolith organs
- Utricle
- Saccule
- Sense acceleration and tilt
- Contain macula
- Utricle
- cavity in the temporal bone near the cochlea
- Hair cells
- act as mechanoreceptors in each of the five vestibular organs
- Head motion causes them to deflect
- Changes hair cell voltage
- Alters neurotransmitter release
- Alters neurotransmitter release
- Changes hair cell voltage
- act as mechanoreceptors in each of the five vestibular organs
- Inner ear
- Sensing movement
- Semicircular canals
- Endolymph
- Ampulla
- Cristae
- Cilia of hair cells project into jellylike cupula which forms an elastic dam
extending to the opposite ampulla wall, with endolymph on both sides of dam.
- Function in pairs
- Endolymph
- Coding of head rotation
- When the head rotates, the inertia of the endolymph causes it to
lag behind, leading to tiny deflections of the hair cells.
- In the absence of any rotation, many afferent neurons from the
semicircular canals have a resting firing rate of about 100 spikes/s.
- This firing rate is high relative to nerve fibres in other sensory systems.
- This firing rate is high relative to nerve fibres in other sensory systems.
- Changes in firing rate are proportional to angular velocity of the head aligned with the canal the neuron is in.
- When the head rotates, the inertia of the endolymph causes it to
lag behind, leading to tiny deflections of the hair cells.
- Coding of direction
- Direction sensitivity arises in part from the anatomical orientation of the organs.
- Utricular macula
- Sensitive to horizontal linear acceleration and gravity
- Sensitive to horizontal linear acceleration and gravity
- Saccular macula
- Sensitive to vertical linear acceleration and gravity
- Sensitive to vertical linear acceleration and gravity
- Direction sensitivity arises in part from the anatomical orientation of the organs.
- Somatogravic illusion
- Semicircular canals
- Vestibular reflexes
- Vestibulo-ocular reflexes
- Angular VOR
- Torsional eye movement
- Six oculomotor muscles rotate eyes
- Mediated in brain stem
- Mediated in brain stem
- Angular VOR
- Vestibulo-spinal reflexes
- Axons from the medial vestibular nucleus descend to reach the spinal cord.
- Stops us falling over
- Axons from the medial vestibular nucleus descend to reach the spinal cord.
- Vestibulo-autonomic reflexes
- Regulates blood pressure (and other things)
- Regulates blood pressure (and other things)
- Vestibulo-ocular reflexes
- Visual-vestibular Integration
- vection
- Gravity stops the illusion so we feel tilted but not upside down when looking at a rotating display
- Gravity stops the illusion so we feel tilted but not upside down when looking at a rotating display
- vection
- Disorders
- Benign paroxysmal positional vertigo
- Dislodged otoconia
- Treated by miraculous head movements
- Treated by miraculous head movements
- Dislodged otoconia
- Mal de Débarquement Syndrome
- Aftereffect of being on a boat
- Aftereffect of being on a boat
- Meniere's Syndrome
- Sudden experience of dizziness, imbalance, and spatial disorientation.
- Sudden experience of dizziness, imbalance, and spatial disorientation.
- Benign paroxysmal positional vertigo
- Alcohol
- Low density
- Absorbs into blood stream and endolymph
- Changes dynamics
- Changes dynamics
- Absorbs into blood stream and endolymph
- Low density
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