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level: Sensory Systems

Questions and Answers List

level questions: Sensory Systems

QuestionAnswer
Define sensory perceptionSensory perception is our conscious interpretation of the external world as created by the brain from the pattern of nerve impulses delivered to it by sensory receptors.
Describe the attributes of a sensory stimulusModality: The form of energy transformed into sensation (the type of stimulus). Intensity: The strength of the stimulus, at or above a threshold level. Duration: The length of time that the stimulus persists. Location: The position of stimulus input.
Describe the different sensory receptors and sensory modalitiesMechanoreceptors – touch, pressure, vibration, stretch, hearing Thermoreceptors – temperature change Photoreceptors – light Chemoreceptors – taste, smell, oxygen and carbon dioxide Osmoreceptors – osmotic pressure of body fluids Nociceptors – pain (fast pricking pain, slow burning pain and heat/cold)
Explain modality in regards to sensory information and coding of sensory stimuliReceptors respond to specific types of stimuli "Labelled line” - receptors of a certain modality transmit their information to specific subsets of neurons on the way to the cortex Some pathways are non-specific (polymodal) due to convergence of inputs from receptors of different modalities.
Explain intensity in regards to sensory information and coding of sensory stimuliFrequency-coding of action potentials Recruitment of additional sensory units by larger stimuli Higher concentrations of neurotransmitter in the synaptic cleft produce larger receptor potentials in the second order neuron
Explain location in regards to sensory information and coding of sensory stimuliReceptive fields Discrimination of stimuli by size, number and overlap of receptive fields “Map strategy” organization of sensory pathways
What is the role of the nerves in processing of visuals, auditory OR tactile information?Nerves are bundled tracts of axons, which carry signals from receptive fields throughout the body to spinal cord or brainstem.
What is the role of the dermatomes in processing of visuals, auditory OR tactile information?Dermatomes are areas of the skin that are supplied by a single spinal nerve, they help relay sensory, motor and autonomic information between the rest of the body and the CNS.
What is the role of the retina in processing of visuals, auditory OR tactile information?The retina is a layer of nervous tissue that covers the back two-third of the eyeball stimulating light so that the sensation of vision can be initiated.
What is the role of the cochlea in processing of visuals, auditory OR tactile information?The external and middle portions of the ear transmit sound waves to the fluid-filled inner ear, amplifying sound energy in the process. Mechanoreceptors in cochlea convert sound waves into action potentials, making hearing possible.
Define 'sensory homunculus"The sensory homunculus is the sensory fields of the body that are mapped in the parietal cortex in a pattern. Body parts of sensory homunculus are proportional to the amount of cerebral cortex devoted to a given body region and to how richly that region is innervated.
Define 'retinotopic map'The retinotopic map is the visual field of the retina is mapped in the occipital cortex.
Define 'tonotopic map'The tonotopic map is the way the auditory cortex is organized, which includes properties such as: Frequency of tones Frequency ratios between harmonics and the pitch of complex sounds Speed and direction of frequency sweeps Sound intensity and location of sound in space