Keeping circadian rhythms synchronized and operating on a 24-hour schedule:
A) is normally impossible because of sleep spindles.
B) requires special photoreceptors in the eye to detect sunlight and communicate this information to the brain.
C) occurs naturally when people are deprived of all time cues.
D) requires the hypothalamus to release the neurotransmitter hypocretin.

Question

Quizplus · Accepted Answer

Keeping circadian rhythms synchronized with a 24-hour schedule requires specialized photoreceptors in the eye to detect sunlight and communicate this information to the brain. These photoreceptors, known as melanopsin cells, are sensitive to blue light and are responsible for signaling the brain to synchronize circadian rhythms with the external environment.

Keeping Circadian Rhythms Synchronized and Operating on a 24-Hour Schedule