Sensory Receptor Cells

• Receptor cell

  A cell that responds to a stimulus
• Receptor cells

  • Transducers
  • Convert energy into electrical impulses within a sensory neuron
  • Often found in sense organs
• Types of receptors

  • Light receptors
  • Chemoreceptors
• Specialized receptors

  Detect a specific type of stimulus and influence the electrical activities of a sensory neuron
• Touch receptors

  Ends of the sensory neurons themselves
• Receptor cell stimulation

  1. Stimulated

  2. Depolarized

  3. If weak, not activated

  4. If strong, activated and transmits impulses to the CNS
• When receptor cells are stimulated, they are depolarized
• If a stimulus is very weak, cells are not sufficiently depolarized and sensory neuron is not activated to send impulses
• If strong enough, sensory neuron is activated and transmits impulses to the CNS
• Sense of touch

  • Humans can distinguish between many different sensations
  • Different pressures feel different
  • Temperature can be detected
• All the different sensations are detected by different types of receptors in the skin
• Pacinian corpuscles

  A type of receptor found deep in the skin
• Areas where Pacinian corpuscles are present

  • Skin of fingers
  • Soles of feet
  • Joints
  • Tendons
  • Ligaments
• Receptors in the skin

  • Range of different receptors present
  • Number of receptors varies in different areas
  • Fingertips have a large number of receptors
  • Back of the finger has lower numbers
  • Different structures and positions within the skin
• Pacinian corpuscles respond to changes in pressure
• When stimulated by pressure, leads to an establishment of a generator potential