Control of Muscle Spindle Sensitivity

Question 1

What is the term defining the shape of a muscle spindle?

Answer 1

FUSIFORM

Question 2

What does each muscle spindle contain, enclosed in a CT capsule?

Answer 2

INTRAFUSAL MUSCLE FIBERS

Question 3

Intrafusal muscle fibers are innervated by small motor neurons from the anterior horn of the SC known as what?

Answer 3

GAMMA MOTOR NEURONS

Question 4

Extrafusal fibers are normal skeletal muscle fibers and are innervated by what?

Answer 4

LARGE ALPHA MOTOR NEURONS

LMNs

Question 5

What do gamma motor neurons regulate and control?

Answer 5

SENSITIVITY OF SPINDLES TO STRETCH
+
LENGTH OF INTRAFUSAL FIBERS

Question 6

Shortening the intrafusal fibers increases tension on _______________, causing increased sensitivity to stretch (and making the 1a neurons more likely to depolarize).

Answer 6

THE SPINDLE

Question 7

Gamma motor neurons are mainly controlled by _____________ _________ coming from supraspinal centers (ie: basal ganglia).

Answer 7

DESCENDING TRACTS

Question 8

What can abnormal gamma activity significantly distort?

Answer 8

MUSCLE TONE and FUNCTION