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Sensory information is interpreted on the basis of frequency of arriving: |
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Action Potentials |
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Conscious awareness of a sensation is called a: |
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Perception |
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Sensory receptors represent the interface between the: |
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Nervous System & External/Internal Environment |
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A sensory receptor detects: |
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An arriving stimulus and translates it into an action potential that can be conducted to the CNS |
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Sensory information that arrives at the CNS is routed according to: |
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The Localization and nature of the stimulus |
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Along sensory pathways, a series of neurons relays information from one point to another, what are the two points? |
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The receptor to another neuron at a specific site in the cerebral cortex |
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Adaptation: |
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Is a reduction in sensitivity in the presence of a constant stimulus. You "adapt" to stimuli that are painless and constant |
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Peripheral adaptation occurs when? |
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The level of receptor activity changes. The receptor responds strongly at first, but thereafter its activity gradually declines |
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What is central adaptation? |
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Example: After being exposed to a new smell, conscious awareness of the stimulus disappears, though sensory neurons are still active |
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Therefore, central adaptation at the subconscious level..... |
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Further restricts the amount of detail that arrives at the cerebral cortex |
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Peripheral adaptation does what? |
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Reduces the amount of information that reaches the CNS |
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3 Classifications of General Senses: |
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Exteroceptors, Proprioceptors, Interoceptors |
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Exteroceptors: |
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Provide information about the external environment |
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Proprioceptors: |
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Report the positions of skeletal muscles and joints |
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Interoceptors: |
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Monitor visceral organs and functions |
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4 Different NATURES of the stimulus: |
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Nociceptors, Thermoreceptors, Mechanoreceptors, Chemoreceptors |
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Nociceptors: |
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Pain receptors. Common in the superficial portions of the skin, joint capsules, periostea of bones & walls of blood vessels |
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What type of Axon Fiber (A, B or C) carries sensations of fast pain or prickling pain? |
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Myleninated Type A Fibers |
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What type of fibers carry sensations of slow pain, or burning and aching pain? |
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Type C Fibers |
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Acute pain is the result of: |
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Tissue injury that can be treated |
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Chronic Pain is: |
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Pain from an injury that persists after tissue structure has been repaired, pain from a disease or pain without a cause |
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Thermoreceptors: |
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Temperature receptors; Free nerve endings in the dermis, skeletal muscles, liver and the hypothalamus. |
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Which receptor, cold or warm, is more numerous? |
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Cold receptors. They are three or four times more numerous than warm receptors. |
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Mechanoreceptors: |
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Tactile receptors; Provide sensations of touch, pressure, vibration. |
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Baroreceptors: |
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Monitor changes in pressure, Free nerve endings, Blood pressure, Lung expansion |
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Proprioreceptors: |
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Monitor postions of joints, the tension in tendons and ligaments, and the state of muscular contraction |
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Tactile Receptors: (Tactile discs/corpuscles, Lamellated corpuscles, Ruffini corpuscles) |
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Free nerve endings to touch and pressure. Near hairs in epidermal. |
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Chemoreceptors: |
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Detect changes in the concentration of specific chemicals, Respond only to water-soluble and lipid-soluble substances |
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Three major somatic sensory pathways (info going in): |
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Posterior column pathway, Anterolateral pathway, Spinocerebellar pathway |
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Posterior Column Pathway: |
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Carries sensations of highly localized ("Fine") touch, pressure, vibration, and proprioception |
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Anterolateral Pathway: |
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Sensations of poorly localized ("Crude) touch, pressure, pain, and temperature |
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Spinocerebrellar Pathway: |
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The cerebellum receives proprioceptive information about the position of skeletal muscles, tendons, and joints from the spinocerebellar pathway |
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Visceral Sensory Pathways: |
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Information is collected by interoceptors monitoring visceral tissues and organs, primarily within the thoracic and abdominal cavities |
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SNS (Info going out) 3 motor pathways: |
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Corticospinal, Medial, Lateral |
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Corticospinal Pathway: |
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Voluntary control over skeletal muscles; Cerebral palsy |
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Medial Pathways: |
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Control gross movement |
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Lateral Pathway: |
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Control distal limb precise movements |
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