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25 Cards in this Set
- Front
- Back
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Receptive field
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-Area whose stimulation results in firing one neuron
-Small receptive field=good acuity; more brain real estate |
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Lateral inhibition
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-Sensory neurons most stimulated inhibit neighboring sensory neurons via interneurons
-Sharpens sensation |
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Illusions
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-The brain receives action potentials from throughout the body.
-These action potentials do not always correctly represent reality |
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Cutaneous sensations
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Mediated by dendritic nerve endings of sensory neurons
Sensations: -Touch -Pressure -Vibration -Temperature -Pain |
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Touch, pressure vibration
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-Sensed by mechanoreceptor cells
-Deformation of the capsule or nerve endings opens pressure-sensitive sodium channels |
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Temperature
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Sensed by thermoreceptor cells
-hot sensed by "capsaicin receptor" ion channel; heat opens ion channel sodium enters, signal to brain "hot" -cold sensed by "menthol receptor"; cold opens ion channel, signal to brain "cold |
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Pain
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Sensed by nociceptive cells responding to chemical, temperature or mechanical stimulus
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Taste
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-Taste cells in taste buds
-Chemoreceptors on microvilli -Ligand binds:taste cell depolarizes, produces action potential, releases neurotransmitter -CN:7,9,12 5 tastes Salt (sodium) Sour (H+) Sweet (sugar) Bitter (quinine) Umami (glutamate) |
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Olfaction
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-Chemoreceptors on cilia of dendrites of sensory neurons
-350 different receptor proteins -Each neuron expresses only one type of receptor -Ligand binds:neuron depolarizes, produces action potential, releases neurotransmitter -Stimulates CN1 |
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Vestibular System
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-Receptors-mechanoreceptor hair cells
-Hair cells stimulate neurons in CN8 -Signal to brainstem -synapse with cranial nerves to eye muscles for tracking -During spin eyes track in opposite direction vestibulo-ocular reflex (VOR) -Vestibular nystagmus |
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Auditory
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-Sounds waves enter outer ear and cause tympanic vibration
-Vibration via malleus, incus and stapes to oval window -Oval window vibrations displace fluid inside the cochlea |
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Scala vestibuli (cochlea)
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Receives pressure at oval window
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Cochlear duct (cochlea)
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has hair cells
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Scala tympani (cochlea)
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Releases pressure at round window
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High Volume
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-More shear force between basilar and tectorial membranes
-Hair cells bend more -More neurotransmitter released |
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Frequency (pitch)
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-Fluid pressure wave has peak at certain point along cochlear duct
-Those cells fire more strongly (and inhibit others) |
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Deafness
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Conduction deafness-impaired conduction from middle to inner ear
Sensorineural deafness-impaired transmission of nerve impulses **hair cells cannot regenerate |
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Retina
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Neural layer of photoreceptor cells
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Cornea
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Light passes through
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Pupil
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light then passes through here after cornea
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Iris
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Muscle that controls how much light gets through
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Lens
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Focuses the light on the retina
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Optic Disc
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neurons gather to exit eye (blind spot)
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Rods
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-Black and White
-Located in periphery of retina -Sensitive to low light -Absorb light in green wavelength -Large ratio of rods to Retinal ganglion cells |
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Cones
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-Color; Blue green,red
-Stimulated by bright light -Each color contains a unique photopigment -Concentrated in fovea centralis -1:1 ration of cones to Retinal ganglion cells -Colorblindness-lack of one of the three types of cones |
