Monosynaptic Stretch

Afferent

• Latin for "ad ferens" = to carry into
• Carries sensory signal from periphery to central nevous system

Role = to carry sensory info from quadriceps muscle to the spinal cord

Efferent

• Latn for "ex ferens" = to carry away from
• Carries motor signal from CNS to periphery

Role = sends motor commands from spinal cord to the quadricep muscle, which causes reflexive contraction of the quadricep muscle.

Proprioceptor

• Latin for "proprius" = one's own
• Sensory organs that send information regarding state (length, tension, joint angle) of the muscle.

Role = to send sensory info about the quadricep muscle via the afferents to the spinal cord.

Muscle Spindle

• stretch receptor in muscle that detects length of muscle
• A proprioceptor

Role = sends information about length/stretch of the quadriceps to the spinal cord via the afferents

Dorsal Root Ganglion

• Collection of cell bodies (somas)
• Associated with afferent fibers
• Bundled together in "ball like" cluster adjacent to the spinal cord

Role = houses nucleus and important machinery for proprioceptor neurons.

Alpha Motor Neuron

• motor neurons located in ventral horn of spinal column

Role = to reciece afferent sensory input and convey motor efferent signals to the quadricep.

Synapse

• Structure at which pre-synaptic chemical neurotransmitter is released onto post-synaptic neuron to cause an "effect"

Role = afferent fiber which synapses onto alpha motor neuron ( uses excititory neurotransmitter glutamate )

= synapse from efferent fiber onto extrafusal quadricep muscle fibers ( useses acyetocholine neurotransmitter )

Neuromuscular Junction (NMJ)

• synaptic connection between the alpha motor neuron , efferent fiber , and quadricep muscle fibers

Role = where acetocholine (ACh) is released, causing muscle contraction

Notes

** Afferents are a part of the muscle spindle **

** Quadripeds vs Bipeds on Dorsal Root Ganglion **