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NEUROPHYSIOLOGY

A(3 fibers from paciniform corpuscles and Rufiini temiinals

Proprioception and Reflex Pathways: II

Alpha motor neurons to extrafusrfl striated muscle end plater

la (Aa) fibers from annulo endings (propnoception)

Alpha motor neuron to extrafusal musde tlber end plates-

Aa fibers from

Golgetype

endings

Detail of musde spindle

Gamma motor neurons to intrafusal striated muscle end plates-

II    (A{J) fibers from flower S| endings (proprioception); from paciniform corpuscles and pacinian corpusdes (pressure)

III    (AR) fibers from free nerve endings and from some specialized endings (pain and some pressure)

IV (unmyelinated) fibers from free nerve endings (pain)

Ib (Au) fibers from Golgi tendon organs (proprioception)

Gamma motor neuron to mtrałusal muscle fiber and plates

II IA(5) fiber from flower spray la (Aa) fiber from annulospiral endings

Figurę 2.26 Muscle and Joint Receptors_

Musde spindles and Golgi tendon organs send afterent signals to the brain to convey the position of limbs and help coordinate muscle movement. Muscle spindles convey information on muscle tension and contraction (dynamie forces) and musde length (static forces). The nuclear bag fibers respond to both dynamie and static forces.

whereas the nuclear chain fibers respontl to static forces. Intrafusal fibers maintain appropriate tension on the nudear bag and nudeat Chain fibers. If the muscle tension is too gioat (e.g., overstretching of musde or too heavy a load), activation of the Golgi tendon organ causes a reflex relaxation of the muscle.

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