AFFERENT INPUTS

D. Muscle Afferents

1. Muscle spindle apparatus afferents

a. mainly in jaw closing muscles (but not jaw openers!)

b. adequate stimulus: muscle stretch

c. central connections

1) monosynaptic excitatory connections to motoneurons of muscles from which they arise
2) projections to higher centers

d. normal function

1) jaw closing muscle tone
2) jaw proprioception
3) jaw reflexes

d. influenced by gamma-efferent system and intrafusal muscle spindle fibers to

1) take up slack to keep afferents in sensitive region during muscle contraction
2) set reflex sensitivity and muscle tone

E. Tendon Afferents (Golgi tendon organs)

1. Mechanoreceptors located at the muscle-tendon junction

2. Adequate stimulus: muscle tension

3. Normal function

a. signal muscle force
b. inhibit muscle contraction to prevent damage from excess force

4. relatively sparse in jaw muscles