Pacinian corpuscle and receptors

• Describe the reflex arc

  stimulus -> receptors -> sensory neurone -> relay neuron -> motor neurone -> effector -> response
• What are benefits of reflex arc?

  • involuntary so it doesn't place demand on the brain
  • protect body from harm such as preventing arm from being burn
  • innate
  • fast so decision making not required
• Why are receptors transducers?

  they convert electrical energy into chemical energy to produce a generator potential
• Describe the pacinian corpuscle

  • type of mechanoreceptors found in the skin
  • each corpuscle has a sensory neurone surrounded by many layers of connective tissue
  • these are separated by gel
• Describe the pacinian corpuscle at rest

  • sodium channels do not allow sodium ions through as it's narrow
  • inside of corpuscle is more negatively charged than outside
  • this is resting potential
• Describe the pacinian corpuscle at activation

  • sodium channels are stretch-mediated, deforming corpuscle and widening sodium channels
  • sodium ions move into the corpuscle and becomes depolarised
  • this is generator potential
  • generator potential activates action potential which is transmitted to the CNS