The pineal gland is sensitive to light.

• A. True
• B. False
• C. Not applicable
• D. Depends on light exposure

Answer: (B)

The key idea here is that the pineal gland is not directly sensitive to light. It doesn’t have photoreceptors of its own. Instead, light information is detected by the retina and conveyed to the brain’s circadian clock, the suprachiasmatic nucleus (SCN). The SCN then uses a neural pathway through several brain regions to the pineal gland. When light is detected, this pathway inhibits melatonin release from the pineal gland; in darkness, melatonin production increases, helping promote sleep. So, while light influences the pineal gland's activity, the gland itself isn’t directly light-sensitive. That’s why the statement is false.