Sensory Receptors

• Sensory Receptors

  • Specialised cells in nervous system
  • Detect energy changes (stimulus) in environment
  • Energy transducers: Convert energy change into electrical energy as nervous impulse
  • Mechanoreceptor - Pressure + Movement
  • Chemoreceptor - Chemicals
  • Thermoreceptor - Heat
  • Photoreceptors - Light
  • Pacinian Corpuscles:
  • Receptor in skin
  • Detects pressure changes
  • Oval-shaped w/a concentric rings of connective tissue wrapped around nerve cell end
  • Pressure change deforms connective tissue rings, push against nerve endings
  • Only sensitive to change not continuous pressure (stop responding)
• Pacinian Corpuscles transmission

  • Nervous system receptor, mechanoreceptor
  • Responds to mechanical stimuli
  • Pressure
  • Deep in skin + joints
  • Neuron end wrapped in connective tissue layers (lamellae)
  • Cell-membrane has special stretch-mediated sodium channels
  • Open Na+ ions when stretched
  • Pressure stimulus pushes lamellae:
  • Deforms sensory neuron membrane
  • Opens stretch-mediated Na+ ion channels
  • Diffuse in, depolarising
  • Create generator potential
  • Greater pressure opens more Na^+ channels
  • Threshold potential reached, action potential is initiated
  • Impulse move to sensory neuron