Role of Sensory Receptors

• What are sensory receptors?

  Specialised cells that detect energy changes in our surroundings
• What is the specificity of sensory receptors?

  They are specific to a single type of stimulus
• What is an energy transducer?

  It is a sensory receptor that converts energy from one form to another
• What types of energy changes do sensory receptors detect?

  • Chemoreceptors: detect chemical energy
  • Mechanoreceptors: detect pressure and touch
  • Sound receptors: detect vibrations in the inner ear
  • Photoreceptors: detect light intensity
• What does the Pacinian corpuscle detect?

  Pressure, touch, or vibrations
• Describe the structure of a Pacinian corpuscle.

  • Layers of connective tissue
  • Neuronal endings in the center
  • Detects pressure through deformation
  • Surrounded by an outer capsule
• What happens when pressure is applied to the Pacinian corpuscle?

  It causes deformation, leading to depolarization of the neuron
• How does the bending of the Pacinian corpuscle affect nerve thresholds?

  The greater the bending, the higher the depolarization and nerve thresholds
• What is the role of calcium ions in the function of sensory receptors?

  Calcium ions are activated during the stimulus response
• What physiological response is associated with the activation of sensory receptors?

  Vasoconstriction
• What can happen if the nerve thresholds are exceeded?

  It could lead to a painful sensation
• what happens when pressure is applied to the Pacinian Corpuscle?


  • pressure causes stretch/deform
  • stretch-mediated sodium channels open
  • sodium diffuses into neurone
  • greater the stimulus the more sodium channels open
  • depolarisation of the neurone is called the generator potential
  • if threshold is reached action potential is initiated