Outline - 4, BIO 2310, Sensory Physiology

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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 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