Physiology · Nerve and Muscle Physiology

Reflex arc and classification of reflexes

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Definition

  • A reflex is a stereotyped, involuntary motor response to an adequate stimulus, via the reflex arc.
  • A spinal reflex is integrated in the spinal cord, e.g. stretch reflex.

Components of the Reflex Arc

  • A spinal reflex arc has five components: receptor, afferent, interneuron, motor neuron, effector.

Components of a spinal reflex arc

Classification of Spinal Reflexes

Reflexes integrated in the spinal cord

Reflex

Stretch reflex (myotatic reflex)

Receptor
Muscle spindle
Synapses
Monosynaptic

Inverse stretch reflex (inverse myotatic reflex)

Receptor
Golgi tendon organ
Synapses
Disynaptic

Withdrawal reflex (flexion reflex)

Receptor
Nociceptors
Synapses
Polysynaptic