Question

In reflex action, the reflex is formed by

• A. Brain- spinal cord- muscles
• B. Receptor- spinal cord- muscles
• C. Muscles- receptors- brain
• D. Muscles- spinal cord- receptor

Answer 1

The correct option is B Receptor- spinal cord- muscles

In a withdrawal reflex, the following actions are carried out:

1. The stimulus is detected by sensory receptors present in the skin.

2. These initiate nerve impulses in the sensory or afferent neurons leading from them to the spinal cord.

3. These impulses enter the spinal cord and initiates impulses in one or more interneurons,

4. Interneurons initiate impulses in one more motor or efferent neurons.

5. The motor neurons then carry these impulses to the effectors or skeletal muscles in which response will be shown. The muscles called flexors are stimulated to contract so that they withdraw the body part whereas the muscles called extensors are inhibited so that they do not extend the body part. The result is that the body part is suddenly. involuntarily withdrawn from the irritating stimulus. - This entire pathway from sensory receptor to sensory neuron to spinal cord to motor neuron to effectors is called the reflex arc.
So, the correct option is option B.