II. SENSORY PHYSIOLOGY
A. Sensation
1. State of external/internal awareness
2. Stimulus
3. Receptor
4. Nerve impulse to brain
B. Characteristics of sensations
1. Projection – phantom pain
2. Adaptation
3. Afterimages
4. Modality
Can discern one sensation from another
C. Receptors
1. Dendrites [organs]
2. Generator potential
D. Classification of receptors
1. Location of stimulus
a. Exteroceptors
b. Enteroceptors = visceroceptors
c. Proprioceptors
Receptors for muscle sense
2. Type of stimulus
a. Mechanoreceptors
b. Thermoreceptors
c. Chemoreceptors
d. Photoreceptors
e. Nociceptors
Pain receptors
E. Cutaneous sensations
1. Receptor fields [area skin whose stimulation results in nerve impulse]
a. 2 point discrimination / threshold
Smallest distance that 2 distinct points can be detected
b. Lateral inhibition
Sharpening of the sensation
2. Tactile sensations
a. Meissner’s corpuscles
Touch corpuscles
b. Hair root plexus
c. Free nerve endings
3. Pressure sensations
a. Pacinian = Lamellated corpuscles
4. Thermal sensations
a. Free nerve endings
5. Pain sensation
a. Free nerve endings
b. Referred pain
F. Proprioceptive sensations (kinesthetic sense)
1. Muscle spindles; intrafusal fibers
stretch receptors
2. Tendon organs =Golgi tendon organs
contraction receptors
3. Misc. joint receptors