LO5: spinal reflex arcs

spinal reflex arcs

neural pathways that produces rapid involuntary somatic or autonomic reflex response to a stimulus

5 components of spinal reflex arc

receptor, sensory neuron, integration centre, motor neuron, effector

somatic reflexes

stimulate skeletal muscle contractions and involve LMN, conduct motor output from spinal cord to skeletal muscle. can be modified by the PMC.

motor output conducted to reflex integration centres via upper motor neurons within corticospinal tract

somatic reflex assessments

condition of spinal cord segments, lower motor neurons, primary motor cortex, corticospinal tracts

patellar reflex

stimulus: tap patellar tendon

normal response: extension at knee (kick)

damage to PMC = hyperreflexia

spinal segment: L2-4

biceps reflex

stimulus: tap at biceps brachii tendon

normal response: flexion at elbow

spinal segment: C5-6

triceps reflex

stimulus: tap to triceps brachii tendon

normal response: extension at elbow

spinal segment: C6-7

plantar reflex

stimulus: stroking of lateral side of sole of the foot

normal response: flexion of toes (>1yr)

damage to PMC or corticospinal tracts = babinski sign

spinal segment: L4-S2