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68 Cards in this Set
- Front
- Back
What is the PNS?
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all neural structures outside the brain and spinal cord
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What does the PNS include?
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sensory receptors, peripheral nerves, associated ganglia, and motor endings
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What is the function of the PNS?
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it provides links to and from the external environment
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What are sensory receptors?
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structures specialized to respond to stimuli
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What happens when sensory receptors are activated?
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it results in depolarization that trigger impulses to the CNS
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What are the five types of receptors?
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1. Mechanoreceptors
2. Thermoreceptors 3. Photoreceptors 4. Chemoreceptors 5. Nocireceptors |
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What are exteroreceptors?
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they are receptors that responds to stimuli outside the body
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What are mechanoreceptors?
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they respond to touch, pressure, vibration, stretch and touch
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What are thermoreceptors?
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receptors that are sensitive to changes in temperature
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What are photoreceptors?
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they respond to light energy (retina)
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What are chemoreceptors?
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they respond to chemicals (smell, taste, changes in blood chemistry)
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What are nocireceptors?
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they are receptors that are sensitive to pain causing stimuli
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Where are exteroreceptors found?
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They are found near the body surface
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What are exteroreceptors sensitive to?
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touch, pressure, pain and temperature
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What organs do exteroreceptors include?
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they include the special sense organs
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What are interoceptors?
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they are receptors that respond to stimuli arising within the body
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Where are interoceptors found?
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found in internal viscera and blood vessels
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What are interoceptors sensitive to?
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they are sensitive to chemical changes, stretch, and temperature changes
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What is the EEG representation of brain waves during death?
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flat one
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What are proprioceptors?
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they respond to degree of stretch of the organs they occupy
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What are the receptor classes by location?
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1. proprioceptors
2. interoceptors 3. exteroceptors |
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Where are proprioceptors found?
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skeletal muscles, tendons, joints, ligaments, and connective tissue coverings of bones and muscles
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What does survival depend on?
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sensation and perception
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What is sensation?
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the awareness of changes in the internal environment and external environment
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What is perception?
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the conscious interpretation of those stimuli
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Where does input come from?
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exteroceptors, interoceptors, proprioceptors
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What are the three main levels of neural integration of the sensory system?
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1. Receptor Level
2. Circuit Level 3. Perceptual Level |
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What is the receptor level of neural integration?
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the sensor receptors
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What is the circuit level of neural integration?
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ascending pathways
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What is the perceptual level of neural integration?
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neuronal circuits in the cerebral cortex
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Processing at the Circuit Level
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chains of three neurons (first, second, third order) conduct sensory impulses upward to the brain
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Where are first order neurons located?
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in dorsal root or cranial ganglia
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What is the function of first order neurons?
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to conduct impulses from the skin to the spinal cord or brain stem
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Where are second order neurons located?
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in the dorsal horn of the spinal cord, or medullary nuclei
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What is the function of second order neurons?
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they transmit impulses to the thalamus or cerebellum
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Where are third order neurons located?
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located in the thalamus
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What is the function of third order neurons?
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conduct impulses to the somatosensory cortex of the cerebrum
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Where does the thalamus project fibers to?
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a. the somatosensory cortex
b. sensory association areas |
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What is a nerve?
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cordlike organ of the PNS made up of peripheral axons enclosed by connective tissue
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What do connective tissue coverings of nerves include?
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a. Endoneurium
b. Perineurium c. Epineurium |
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What is the endoneurium?
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loose connective tissue that surrounds axons
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What is the perineurium?
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coarse connective tissue that bundles fibers into fasicles
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What is the epineurium?
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tough fibrous sheath around a nerve
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What are the two division of the nerves?
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Sensory and motor divisions
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What do sensory (afferent) nerves do?
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carry impulse to the CNS
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What do motor (efferent) nerves do?
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carry impulses from CNS
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What are mixed nerves?
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sensory and motor fibers carry impulses to and from CNS
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What is the most common type of nerve?
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a mixed nerve
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Why is damage to nerve tissue serious?
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because mature neurons are amitotic
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If the soma of a damaged nerve remains intact what can be done?
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the damage can be repaired
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How many cranial nerves are there?
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12 that arise from the brain
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What type of functions do the cranial nerves have?
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sensory, motor, or both
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How is each cranial nerve identified?
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by a name and roman numerals
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How many cranial nerves carry parasympathetic fibers?
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4
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What do these cranial nerves serve?
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muscles and glands
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What does regeneration of nerve fibers involve?
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a. macrophages
b. schwann cells c. axons |
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What do the macrophages do?
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remove debris
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What do the schwann cells do?
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from regeneration tube and secrete growth factors
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What do the axons do?
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regenerate damaged part
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What is the soma of the nerve?
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cell body
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What is cranial nerve I?
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olfactory nerve
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Where does the olfactory nerve arise from?
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from the olfactory epithelium
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What does the olfactory nerve pass through?
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the cribriform plate of the ethmoid bone
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Where does the olfactory nerves fibers run through?
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the olfactory bulb and terminate in the primary olfactory nerves
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What is the function of the olfactory nerve?
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carrying afferent impulses for smell
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What is cranial nerve II?
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optic nerve
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Where does the optic nerve pass through?
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the optic canals and converge at the optic chiasm, the continue to the thalamus where they synapse
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What is the function of the optic nerve?
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carrying afferent impulses for vision
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