Different components of reflex arc are given below -
I. Effector organ
II. Interneuron
III. Motor nuuron
IV. Sensory neuron
V. Sensory receptor
Choose the correct order an action potential follows after a sensory receptor is stimulated -
V, IV, II, III, I
— Concept: This question tests the understanding of the sequential pathway of an action potential in a reflex arc , which…Concept: This question tests the understanding of the sequential pathway of an action potential in a reflex arc, which is the neural pathway that mediates a reflex action.
Why (B) is correct:
The correct order for an action potential in a reflex arc is:
- Sensory receptor (V): Detects the stimulus.
- Sensory neuron (IV): Transmits the afferent impulse from the receptor to the Central Nervous System (CNS).
- Interneuron (II): Located in the CNS (spinal cord), it processes the information and relays it to the motor neuron. This is also called a relay neuron.
- Motor neuron (III): Transmits the efferent impulse from the CNS to the effector organ.
- Effector organ (I): A muscle or gland that responds to the stimulus.
Therefore, the sequence V IV II III I is correct.
Why other options are wrong:
- A) V, IV, III, II, I: Incorrect order of interneuron and motor neuron.
- C) V, III, IV, I, II: Completely incorrect sequence, mixing up sensory and motor pathways.
- D) V, II, IV, III, I: Incorrect placement of interneuron before the sensory neuron transmits the signal to the CNS.
NEET Tip: Remember the acronym SAME (Sensory Afferent, Motor Efferent) to recall the direction of nerve impulses. Also, think of the reflex arc as a 'chain of command' from stimulus to response.
Correct Answer: (B)
V, IV, II, III, I