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2011-10-26 16:47:07
General Senses

General Senses
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  1. Any stimuli the body is aware of
  2. What are we not aware of? And why?
    • X-rays
    • Ultra high frequency sound waves
    • UV Light
    • Because we have no sensory receptors for those stimuli
  3. The conscious awareness & interpretation of a sensation
  4. Precisely localization & identification
  5. Where are our memories of perceptions stored?
  6. Has no structural specializations in free nerve endings that provide us with pain, tickle, itch, temperatures
    General Sensory Receptors (Somatic Receptors)
  7. Has some structural specializations in receptors for touch, pressure & vibration
    General Sensory Receptors (Somatic Receptors)
  8. Very complex structures---vision, hearing, taste, & smell
    Special Sensory Receptors (Special Sense Receptors)
  9. How are sensory receptors classified?
    • 1. Structural classification
    • 2. Location of receptors & origin of stimuli
    • 3. Type of stimuli they detect
  10. Structural Classification of Receptors:
    – bare dendrites
    – pain, temperature, tickle, itch & light touch
    Free nerve endings
  11. Structural Classification of Receptors:
    – dendrites enclosed in connective tissue capsule
    – pressure, vibration & deep touch
    Encapsulated nerve endings
  12. Structural Classification of Receptors:
    – specialized cells that respond to stimuli
    – vision, taste, hearing, balance
    Separate sensory cells
  13. Classification by Location:
    – near surface of body
    – receive external stimuli
    – touch, pressure, pain, vibration & temperature
  14. Classification by Location:
    – monitors internal environment (BV or viscera)
    – not conscious except for pain or pressure
  15. Classification by Location:
    – near surface of body
    – receive external stimuli
    – touch, pressure, pain, vibration & temperature
  16. Classification by Location:
    – monitors internal environment (BV or viscera)
    – not conscious except for pain or pressure
  17. Classification by Location:
    – muscle, tendon, joint & internal ear
    – senses body position & movement
  18. Classification by Stimuli Detected:
    – detect pressure or stretch
    – touch, pressure, vibration, hearing, proprioception, equilibrium & blood pressure
  19. What detects temperature?
  20. Detect damage to tissues
  21. Detect light
  22. Detect molecules
    – taste, smell & changes in body fluid chemistr
  23. Name the 4 Somatic Tactile Sensations
    • 1. Touch
    • 2. Pressure
    • 3. Pain
    • 4. Temperature
  24. Flattened dendrites touching cells of stratum basale
    Used in discriminative touch
    Merkel's Disc
  25. Dendrites enclosed in CT in dermal papillae of hairless skin
    Discriminative touch & vibration-- rapidly adapting • Generate impulses mainly at onset of a touch
    Meissner's Corpuscle
  26. Free nerve endings found around follicles, detects movement of hair
    Hair Root Plexus
  27. Found deep in dermis of skin
    Detect heavy touch, continuous touch, & pressur
    Ruffini Corpuscle
  28. Onion-like connective tissue capsule enclosing a dendrite
    Found in subcutaneous tissues & certain viscera Sensations of pressure or high-frequency vibration
    Pacinian Corpuscle
  29. Pain receptors
  30. Free nerve endings found in every tissue of body except ____ _______
    the brain
  31. Stimulated by excessive distension, muscle spasm, & inadequate blood flow
    Pain sensation
  32. What causes the release of chemicals such as K+, kinins or prostaglandins that stimulate nociceptors
    Tissue injury (a pain sensation)
  33. Little adaptation occur
    Pain sensations
  34. Pain that is felt just deep to the skin overlying the stimulated organ or in a surface area far from the organ.
    Visceral pain
  35. Skin area & organ are served by the same segment of the _____ _____
    Spinal cord
  36. Felt in skin along left arm since both are supplied by spinal cord segment T1-T5
    Heart attack
  37. block formation of prostaglandins that stimulate nociceptors
    Aspirin & Ibuprofen
  38. Blocks conduction of nerve impulses along pain fibers
  39. Lessens the perception of pain in the brain.
  40. Awareness of body position & movement
    – walk or type without looking
    – estimate weight of objects
    Proprioceptive Sensations
  41. Sensation that adapts only slightly
  42. Musle spindles, Golgitendon organs and joint receptor
  43. Specialized intrafusal muscle fibers enclosed in a CT capsule and innervated by gamma motor neurons
    Muscle Spindles
  44. Stretching of the muscle stretches the _______ _______ sending sensory information back to the CN
    muscle spindles
  45. Found at junction of tendon & muscle
    Golgi Tendon Organs
  46. Consists of an encapsulated bundle of collagen fibers laced with sensory fibers
    Golgi Tendon Organs
  47. When the tendon is overly stretched, sensory signals head for the _______ & resulting in the muscle’s __________
    CNS; relaxation
  48. Joint Receptors:
    Found in joint capsule
    Respond to pressure
    Ruffini corpuscles
  49. Found in connective tissue around the joint
    Respond to acceleration & deceleration of joints
    Pacinian corpuscles
  50. First-order neuron conduct impulses to ________ or _______ ______
    brainstem; spinal cord
  51. What type of nerve: first-order neuron conduct impulses to brainstem or spinal cord
    Either spinal or cranial nerves
  52. conducts impulses from spinal cord or brainstem to thalamus--cross over to opposite side before reaching thalamus
    Second-order neurons
  53. Conducts impulses from thalamus to primary somatosensory cortex (postcentral gyrus of parietal lobe)
    Third-order neuron
  54. vibration, discriminative touch, weight discrimination & stereognosis
    Touch and Pressure Proprioception
  55. Signals travel up spinal cord in posterior column and synapse in _________ _______ or __________
    nucleus gracilus or cuneatus
  56. Fibers cross-over in medulla to become the medial lemniscus pathway ending in __________
  57. What do thalamic fibers reach?
    Somatosensory cortex
  58. Spinothalamic Pathways:
    What do anterior and lateral spinothalamic tract carry?
    pain & temperature
  59. Spinothalamic Pathways:
    First cell body in ______ with synapses in cord
  60. Spinothalamic Pathways:
    In gray matter of cord, sends fibers to other side of cord & up through white matter to synapse in thalamus
    2nd cell body
  61. In thalamus projects to cerebral cortex
    3rd cell body
  62. Sensory Innervation for the Head and Face:
    Provides touch and pressure and pain and temperature for the face and front of the head
    Trigeminal Cranial nerve (CN V)
  63. Somatosensory Map of Postcentral Gyrus:
    Proportional to number of sensory receptors
    Proportional to the sensitivity of each part of the body
    Relative sizes of cortical areas
  64. Sensory Pathways to the Cerebellum:
    Major routes for proprioceptive signals to reach the cerebellum
    • 1. anterior spinocerebellar tract
    • 2. posterior spinocerebellar tract
  65. Used by cerebellum for adjusting posture, balance & skilled movements
    Subconscious information
  66. Sensory Pathways to the Cerebellum:
    Signal travels up to same side of the ________ ________ _________
    inferior cerebellar peduncle