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Which are the two restorative processes that regulate the human body’s pattern of sleepiness and alertness throughout the day?

  • A
    Light/dark homeostasis and the circadian dysrhythmia.
  • B
    Light/dark homeostasis and the parasomnia rhythm.
  • C
    Sleep/wake homeostasis and the parasomnia process.
  • D
    Sleep/wake homeostasis and the circadian rhythm.
Have you ever noticed that you feel more alert at certain times of day, and feel more tired at other times? Those patterns are a result of two body systems: sleep/wake homeostasis and your circadian rhythm, or internal body clock. These systems determine your sleep drive, or your body’s need for sleep, at any given time.
  • Sleep/wake homeostasis balances our need for sleep, called a “sleep drive” or “sleep pressure,” with our need for wakefulness. When we’ve been awake for a long period of time, our sleep drive tells us that it’s time to sleep. As we sleep, we regain homeostasis and our sleep drive diminishes. Finally, our need for alertness grows, telling us that it’s time to wake up.
  • Our circadian rhythm approximates a homeostasis in coordination with environmental cues like sunlight. Because of our circadian rhythm, our alertness level dips and rises throughout each 24-hour period, impacting the amount of sleepiness and wakefulness we experience during the day.

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