Receptors of Somatic Sensation

1
Receptors of Somatic Sensation

• Mechanoreceptors of the skin
• Free nerve ending
• Merkels disk
• Meissners corpuscle
• Pacinian corpuscle
• Hair follicle receptor

2
Mechanoreceptors of the skin

• Testing
• Receptive field
• Two point discrimination
• Frequency sensitivity
• Vibration and the Pacinian corpuscle

3
Nociception

• Receptors
• Mechanical
• Thermal
• Chemical
• Polymodal

4
Thermoreception

• Warm receptors
• Cold receptors

5
Proprioception

• Joint receptors
• Muscle receptors
• Golgi tendon organs
• Muscle spindles

6
Stevens Rule

• Ik(S-S0)n
• ISensation intensity
• kProportionality constant
• SStimulus intensity
• S0Threshold stimulus intensity

7
Primary Afferent Nerves

• Proprioceptors A?, large and fast
• Mechanoreceptors of skin A?, intermediate size
  and speed
• Pain, Temperature A?, intermediate size and
  speed
• Pain C Small and slow and unmyelinated

8
Ascending Pathways of Somatic Sensation

• Dorsal column/medial lemniscal pathway
• Spino-thalamic path

9
Organization of the Spinal Cord