Question

Which is the correct sequence of the components of a reflex arc?

• A. Receptors → Muscle → Sensory neuron → Motor neuron → Spinal cord
• B. Receptors → Motor neuron → Spinal cord→ Sensory neuron→ Muscle
• C. Receptors → Spinal cord → Sensory neuron → Motor neuron→ Muscle
• D. Receptors → Sensory neuron → Spinal cord→ Motor neuron→ Muscle

Answer 1

The correct option is D

Receptors → Sensory neuron → Spinal cord→ Motor neuron→ Muscle

The correct option is D.

Explanation for correct option:

• The pathway taken by a stimulus to move from the receptor to the effector organ to create a response in the body is known as the reflex arc.
• The stimulus is first received by the receptors present in the body. These receptors transfer the information about the stimulus to the sensory neurons.
• The sensory neurons then transmit the information to the spinal cord of the central nervous system.
• The spinal cord processes the information and transmits the processed information to motor neurons that will then transfer the information to the effector organs, like muscles and glands, to create a response.

Explanation for incorrect options:

Option A:

• The receptors first transfer the stimulus to the sensory neuron, not the muscles. Hence, this option is incorrect.

Option B:

• The motor neuron receives the information from the central nervous system, not from the receptors. Hence, this option is incorrect.

Option C:

• Receptors cannot directly transmit the information to the spinal cord. The transmission occurs via sensory neurons. Hence, this option is incorrect.

Final answer: Therefore, the correct sequence of the components of a reflex arc is-

Receptors → Sensory neuron → Spinal cord→ Motor neuron→ Muscle