Optometry Admission Test (OAT) Practice

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Study for the Optometry Admission Test (OAT). Dive into multiple choice questions, each with explanations and helpful hints. Enhance your knowledge and prepare for success in your exam!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

Which hormone is responsible for maintaining circadian rhythms?

Testosterone
Estrogen
Melatonin
Progesterone

The correct answer is: Melatonin

Melatonin is the hormone primarily responsible for regulating circadian rhythms, which are the natural physiological processes that cycle roughly every 24 hours, including sleep-wake cycles. Produced by the pineal gland in response to darkness, melatonin levels typically rise in the evening, promoting sleepiness and helping to signal to the body that it is time to rest. This process is crucial for synchronizing the body's internal clock with the external environment, allowing for proper rest and recovery. The natural increase in melatonin at night and its decrease during daylight hours assist in maintaining a regular sleep schedule and overall circadian rhythm. In contrast, other hormones like testosterone, estrogen, and progesterone are more involved in reproductive functions and other biological processes, rather than directly influencing the circadian rhythms that regulate sleep and wakefulness.