Sensory Receptors and Neural Pathways (6A) - MCAT Psychological and Social Foundations
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What is the optic chiasm?
What is the optic chiasm?
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Partial crossing of optic nerve fibers. Where nasal fibers cross to opposite hemisphere.
Partial crossing of optic nerve fibers. Where nasal fibers cross to opposite hemisphere.
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Which thalamic nucleus relays visual information from the optic tract to primary visual cortex?
Which thalamic nucleus relays visual information from the optic tract to primary visual cortex?
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Lateral geniculate nucleus (LGN). Thalamic relay station for visual processing.
Lateral geniculate nucleus (LGN). Thalamic relay station for visual processing.
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Which thalamic nucleus relays auditory information to primary auditory cortex?
Which thalamic nucleus relays auditory information to primary auditory cortex?
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Medial geniculate nucleus (MGN). Processes tonotopic information from inferior colliculus.
Medial geniculate nucleus (MGN). Processes tonotopic information from inferior colliculus.
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Which thalamic nucleus relays auditory information to the primary auditory cortex?
Which thalamic nucleus relays auditory information to the primary auditory cortex?
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Medial geniculate nucleus (MGN). Thalamic relay station for auditory processing.
Medial geniculate nucleus (MGN). Thalamic relay station for auditory processing.
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What is the primary sensory cortex for vision (name and lobe)?
What is the primary sensory cortex for vision (name and lobe)?
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Primary visual cortex (V1) in occipital lobe. First cortical area processing visual information.
Primary visual cortex (V1) in occipital lobe. First cortical area processing visual information.
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What is the primary sensory cortex for audition (name and lobe)?
What is the primary sensory cortex for audition (name and lobe)?
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Primary auditory cortex in temporal lobe. First cortical area processing sound information.
Primary auditory cortex in temporal lobe. First cortical area processing sound information.
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What is the primary sensory cortex for somatosensation (name and lobe)?
What is the primary sensory cortex for somatosensation (name and lobe)?
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Primary somatosensory cortex in parietal lobe. Processes touch, pressure, temperature, and pain.
Primary somatosensory cortex in parietal lobe. Processes touch, pressure, temperature, and pain.
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What term describes a sensory receptor's baseline level of activity without stimulation?
What term describes a sensory receptor's baseline level of activity without stimulation?
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Spontaneous firing (baseline activity). Receptors fire at low rates even without stimulation.
Spontaneous firing (baseline activity). Receptors fire at low rates even without stimulation.
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Which sensory pathway is the major exception to the rule that sensory input relays through the thalamus?
Which sensory pathway is the major exception to the rule that sensory input relays through the thalamus?
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Olfaction (smell). Bypasses thalamus, projects directly to cortex.
Olfaction (smell). Bypasses thalamus, projects directly to cortex.
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Which thalamic nucleus is the primary relay for visual information to primary visual cortex?
Which thalamic nucleus is the primary relay for visual information to primary visual cortex?
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Lateral geniculate nucleus (LGN). Thalamic relay station for vision before reaching V1.
Lateral geniculate nucleus (LGN). Thalamic relay station for vision before reaching V1.
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Which thalamic nucleus is the primary relay for auditory information to auditory cortex?
Which thalamic nucleus is the primary relay for auditory information to auditory cortex?
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Medial geniculate nucleus (MGN). Thalamic relay station for hearing before reaching A1.
Medial geniculate nucleus (MGN). Thalamic relay station for hearing before reaching A1.
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Which thalamic nucleus is the primary relay for somatosensory information to somatosensory cortex?
Which thalamic nucleus is the primary relay for somatosensory information to somatosensory cortex?
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Ventral posterolateral nucleus (VPL). Relays body sensations (not face) to primary somatosensory cortex.
Ventral posterolateral nucleus (VPL). Relays body sensations (not face) to primary somatosensory cortex.
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Identify the receptor type that detects mechanical deformation such as touch, pressure, and vibration.
Identify the receptor type that detects mechanical deformation such as touch, pressure, and vibration.
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Mechanoreceptors. Respond to physical distortion of cell membrane.
Mechanoreceptors. Respond to physical distortion of cell membrane.
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Identify the correct order of the visual pathway from retina to primary visual cortex.
Identify the correct order of the visual pathway from retina to primary visual cortex.
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Retina → optic nerve → LGN → optic radiations → V1. Visual signals relay through thalamus before reaching cortex.
Retina → optic nerve → LGN → optic radiations → V1. Visual signals relay through thalamus before reaching cortex.
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Which sensory receptor type responds primarily to light (photons) in the retina?
Which sensory receptor type responds primarily to light (photons) in the retina?
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Photoreceptors. Light-sensitive cells containing photopigments.
Photoreceptors. Light-sensitive cells containing photopigments.
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Which retinal photoreceptors mediate color vision and high visual acuity in bright light?
Which retinal photoreceptors mediate color vision and high visual acuity in bright light?
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Cones. Contain photopigments for red, green, or blue light.
Cones. Contain photopigments for red, green, or blue light.
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Which retinal photoreceptors support color vision and high visual acuity?
Which retinal photoreceptors support color vision and high visual acuity?
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Cones. Contain opsins for red, green, or blue light; concentrated in fovea.
Cones. Contain opsins for red, green, or blue light; concentrated in fovea.
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Which somatosensory receptors detect light touch and flutter in glabrous skin?
Which somatosensory receptors detect light touch and flutter in glabrous skin?
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Meissner corpuscles. Rapidly adapting mechanoreceptors in hairless skin areas like fingertips.
Meissner corpuscles. Rapidly adapting mechanoreceptors in hairless skin areas like fingertips.
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Which somatosensory receptors detect deep pressure and vibration?
Which somatosensory receptors detect deep pressure and vibration?
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Pacinian corpuscles. Large, rapidly adapting mechanoreceptors sensitive to high-frequency vibrations.
Pacinian corpuscles. Large, rapidly adapting mechanoreceptors sensitive to high-frequency vibrations.
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Which somatosensory receptors detect skin stretch and sustained pressure?
Which somatosensory receptors detect skin stretch and sustained pressure?
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Ruffini endings. Slowly adapting mechanoreceptors that signal continuous deformation.
Ruffini endings. Slowly adapting mechanoreceptors that signal continuous deformation.
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Which somatosensory receptors detect temperature and pain (noxious stimuli)?
Which somatosensory receptors detect temperature and pain (noxious stimuli)?
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Free nerve endings (thermoreceptors and nociceptors). Unmyelinated nerve endings that respond to extreme temperatures and tissue damage.
Free nerve endings (thermoreceptors and nociceptors). Unmyelinated nerve endings that respond to extreme temperatures and tissue damage.
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What is the correct order of the auditory pathway from cochlea to cortex?
What is the correct order of the auditory pathway from cochlea to cortex?
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Cochlea → brainstem → inferior colliculus → MGN → A1. Sound ascends through brainstem nuclei and thalamus to temporal cortex.
Cochlea → brainstem → inferior colliculus → MGN → A1. Sound ascends through brainstem nuclei and thalamus to temporal cortex.
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Which thalamic nucleus relays visual information to primary visual cortex?
Which thalamic nucleus relays visual information to primary visual cortex?
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Lateral geniculate nucleus (LGN). LGN processes visual signals before sending to occipital lobe.
Lateral geniculate nucleus (LGN). LGN processes visual signals before sending to occipital lobe.
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What is the key functional difference between rods and cones?
What is the key functional difference between rods and cones?
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Rods: low light, low acuity; cones: color, high acuity. Rods excel in darkness; cones provide sharp, colorful daylight vision.
Rods: low light, low acuity; cones: color, high acuity. Rods excel in darkness; cones provide sharp, colorful daylight vision.
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Which thalamic nucleus relays auditory information to primary auditory cortex?
Which thalamic nucleus relays auditory information to primary auditory cortex?
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Medial geniculate nucleus (MGN). MGN in thalamus processes sound before cortical analysis.
Medial geniculate nucleus (MGN). MGN in thalamus processes sound before cortical analysis.
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What is a sensory receptor in terms of transduction and the type of stimulus it detects?
What is a sensory receptor in terms of transduction and the type of stimulus it detects?
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A specialized cell that transduces a specific stimulus into neural signals. Receptors are specialized for one stimulus type and convert it to action potentials.
A specialized cell that transduces a specific stimulus into neural signals. Receptors are specialized for one stimulus type and convert it to action potentials.
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Which thalamic nucleus relays visual information to the primary visual cortex?
Which thalamic nucleus relays visual information to the primary visual cortex?
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Lateral geniculate nucleus (LGN). Part of thalamus that processes and relays retinal input to V1.
Lateral geniculate nucleus (LGN). Part of thalamus that processes and relays retinal input to V1.
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Which sensory modality bypasses the thalamus on its initial route to cortex?
Which sensory modality bypasses the thalamus on its initial route to cortex?
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Olfaction (smell). Olfactory signals project directly to cortex without thalamic relay.
Olfaction (smell). Olfactory signals project directly to cortex without thalamic relay.
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What is tonotopic organization in the cochlea?
What is tonotopic organization in the cochlea?
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Base codes high frequency; apex codes low frequency. Frequency mapping along cochlear length enables pitch discrimination.
Base codes high frequency; apex codes low frequency. Frequency mapping along cochlear length enables pitch discrimination.
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What is the main somatosensory pathway for pain and temperature?
What is the main somatosensory pathway for pain and temperature?
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Spinothalamic (anterolateral) pathway. Crosses spinal cord to carry nociceptive and thermal signals.
Spinothalamic (anterolateral) pathway. Crosses spinal cord to carry nociceptive and thermal signals.
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