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7 Cards in this Set
- Front
- Back
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Tactile receptors - 5 types |
Free nerve endings - sensitive touch, pressure Root hair plexus -monitors distortions and movement Merkel discs -fine touch, pressure receptors Meissners capuscles- sensations of touch, pressure and low vibration Pacinian corpuscles -deep pressure, fingers and genitalia Ruffini corpuscles -pressure and distortion of skin- deep |
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Lateral inhibition |
This is where a Neuron which is excited will reduce activity in other neighbouring neurons Occurs in retina and skin also |
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Mechanoreceptors |
A mechanical distortion (skin) causes opening of membrane and influx of ion channels- inflow of positive charged ions The actio potential transmits a signal to the cns |
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Ocular muscles |
Intra ocular muscles- control pupil diameter Extra - move eyeball in socket and innervated with specific cranial nerves Paired extra ocular muscle action- both eyes together |
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5 functional types of eye movements |
Gaze stabilising mechanisms; 1- optokinetic reflex 2- vestibular ocular reflex
Gaze shifting mechanisms; 3- saccadic movements 4- smooth pursuit 5- vergence movement |
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Nystagmus |
Alternation between slow drift and rapid saccades Can be abnormal in those with leisons |
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Vestibular ocular reflex |
Maintaining gaze position despite head movement Occurs from activation of the vestibular system Stabilise image on retina during head movements by producing eye movements in the opposite direction to preserve the image on the centre of the visual field Impaired = hard to read print Damage can lead to vestibular nystagmus Rotation of head= inhibitory signal to the extra ocular muscles, and excitatory on other side- compensatory movement Driven by vestibular apparatus in the inner ear |
