Chapter 50

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Chapter 50
2011-04-13 22:58:23
Bio II

Midterm 2
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  1. sensory reception
    detection of a stimulus by sensory cells
  2. sensory transduction
    the conversion of a physical o chemical stimulus to a change in the membrane potential of a sensory receptor
  3. receptor potential
    change in membrane potential; are graded, as in their magnitude varies with the strength of the stimulus
  4. transmission
    action potentials!
  5. perception
    not so important; actions potentials have reached the brain and neurons process this input; constructs that don't exist outside of the brain
  6. mechanoreceptor
    responsible for touch, hearing, pressure; sense physical deformation; bending of an external structure generates tension that alters the permeability of ion channels
  7. chemoreceptors
    responsible for smell & taste; can be general and transmit info about total solute concentration or specific and can respond to individual molecules
  8. photoreceptors
    responsible for vision (rods and cones); absorb photons
  9. thermoreceptors
    detect heat and cold; located in skin and anterior hypothalamus; send signals to body's thermostat (hypothalamus)
  10. pain receptors (noiceptors)
    naked dendrites that respond to noxious (harmful) stimuli and trigger defensive reactions
  11. statocysts
    sensory organs that sense gravity and maintain equilibrium; common type consists of a layer of cilliated receptor cells surrounding a hollow chamber that contains statoliths (grains of sand)
  12. sense of touch
    a what, where and how much system
  13. auditory system
    a what and how much system; not where not where NOT where
  14. olfactory system
    ONLY what; kind of how much; again NOT WHERE
  15. compound eyes
    insects and crustaceans; consists of up to several thousand light detectors called ommatidia each with it's own light focusing lense; very effective @ detecting movement/color
  16. single-lens eye of invertebrates
    works like a camera; light enters through pupil and amount let it is determined by the iris which either dilates or contracts; lens behind all this moves either forward or back to focus
  17. humans and mammals focus by changing the shape of the lens (not moving it back or forwards); the lens is _______ when focusing on a close object and __________ when focusing on a far-away object
    spherical; flat
  18. retinal
    light absorbing molecule found in photoreceptors (is bound to an opsin)
  19. rhodopsin
    visual pigment found in rods; made up of retinal & a certain opsin; bleaching = when it absorbs light one bond in the retinal goes from cis to trans (bent to straight) and this causes a destabilization/activation