Five Major Types of Reflexes: Classification & Examples

Reflexes are rapid, involuntary responses mediated by neural circuits. A classic functional classification includes five types:

1. Simple (Unconditioned) Reflex

• Hardwired, monosynaptic or polysynaptic spinal/brainstem arcs.
• Examples: Stretch reflex (knee‑jerk), withdrawal reflex, pupillary light reflex, gag reflex.

2. Conditioned (Learned) Reflex

• Acquired via associative learning (Pavlovian/classical or operant).
• Example: Salivation to bell (Pavlov's dogs); fear response to previously neutral stimulus.

3. Withdrawal (Flexor) Reflex

• Protective response to noxious stimulus.
• Polysynaptic: Interneurons activate flexors, inhibit extensors ipsilaterally.
• Example: Hand withdrawal from hot surface.

4. Crossed‑Extensor Reflex

• Contralateral extensor activation concurrent with ipsilateral withdrawal.
• Maintains postural stability during withdrawal.
• Example: Stepping on sharp object → ipsilateral leg flexes, contralateral extends for support.

5. Segmental (Spinal) Reflex

• Confined to one or few spinal segments; no supraspinal involvement.
• Includes stretch reflex, Golgi tendon organ reflex (inverse stretch), flexor withdrawal.
• Clinically tested to localize spinal cord level.

Additional Reflex Categories

• Autonomic reflexes: Baroreceptor, chemoreceptor, micturition, defecation.
• Postural / Tonic reflexes: Vestibulospinal, reticulospinal (e.g., tonic labyrinthine).
• Primitive / Developmental reflexes: Moro, grasp, Babinski (pathologic if persistent).