Sensory & Motor

Question 1

What 2 things maintain normal tone?

Answer 1

Sensory fibers from muscle spindles that excite motor neurons in the spinal cord and descending motor tracts.

Question 2

Deep tendon reflexes are caused by activation of what pathway?

Answer 2

Pulses in the muscle spindles and activation of motor neurons in the spinal cord.

Question 3

Mechanisms of lower motor neuron signs

Answer 3

Reduce sensory input to the cord from the muscle spindles, or reduce motor output to the muscle from the spinal cord.

Question 4

Differences in dorsal and ventral peripheral nerve lesions.

Answer 4

Dorsal - loss of sensation, no atrophy

Ventral - loss of movement, atrophy and fasciculations

Question 5

Acute decreased muscle tone followed by chronic muscle tone is characteristic of?

Answer 5

Descending tract lesions (upper motor neuron)