SCS.F | Sleep Mechanisms |

SCS.F | Sleep Mechanisms

When you’re asleep, there are two biological mechanisms–circadian rhythm and homeostasis–that work together to regulate when you are awake or asleep.

Finding Balance

Circadian rhythms direct a wide variety of functions from daily fluctuations in wakefulness to body temperature, metabolism, and the release of hormones. Ever notice that you tend to start getting sleepy around the same time and usually wake up around the same time in the morning, even without an alarm clock? Most adults have their lowest energy levels between 2 and 4 in the morning, which usually works out pretty well. Unfortunately, the next sleepiest time as between 1 and 3 in the afternoon.

That’s the hypothalamus directing the circadian rhythms – the timing of your sleep. Your body’s biological clock is based on a roughly 24-hour day. Circadian rhythms synchronise with environmental cues (light, temperature) about the actual time of day, but they continue even in the absence of cues.

Though food doesn’t change your circadian rhythms, it can affect how drowsy you are. Foods high in tryptophan, like bananas, sees, tuna, turkey, and milk, can make you sleepier, as will foods that are higher in carbohydrates. Conversely, foods that are high in tyramine, like bacon, pepperoni, eggplant, avocado, and nuts are more likely to keep you awake.

Have you ever heard of “jet lag?” That’s when your circadian rhythm is messed up when your brain finds itself in a place where the sun sets and rises at different times that you are used to, so it tells you to sleep in the early evening or middle of the night depending on what time zone you’ve traveled from. Once you’ve been in the new environment for a few days your brain figures out what’s going on and you go back to a regular schedule…until, of course, you cross back over time zones to home and you’re all messed up again.

Homeostasis

Sleep-wake homeostasis keeps track of your need for sleep. The homeostatic sleep drive reminds the body to sleep after a certain time and regulates sleep intensity. This sleep drive gets stronger every hour you are awake and causes you to sleep longer and more deeply after a period of sleep deprivation. Ever try really hard to stay up late at night and then the next morning you wake up really groggy, like you’ve been asleep for a week? That’s because your brain realizes that you’re up late but it expects to wake you at the same time in the morning, so it intensifies your sleep to make sure that it can get everything done before you wake up, kind of like your brain is cramming for an exam.

So now you know everything that there is to know about how sleep works! Next we’re going to talk about how that applies to living in space and under the sea in the Hab.

Curriculum Reference Links

Biological World / Systems and Interactions / 6: Students should be able to evaluate how human health is affected by: inherited factors and environmental factors including nutrition; lifestyle choices; examine the role of micro-organisms in human health

10 Fun Facts: The Hab

1. Aquarius is the the world’s only permanent undersea research station.

2. Most missions last about two or three weeks.

3. Fabien Cousteau, grandson of Jacques Cousteau, beat his grandfather’s record month-long underwater expedition by spending 31 days on the Aquarius Reef Base in 2014.

4. The lab is used by NASA, the US Navy, and researchers and educators from around the globe for training and research.

5. The internet connection is better in the Hab than at many places above the water.

6. You have to swim underneath the facility in order to enter it.

7. Crew members are called aquanauts (NOT aquaNUTS!)

8. In 1994, a crew of scientists and divers had to evacuate Aquarius and climb up a rescue line to the surface in 15-foot seas after one of the habitat’s generators caught fire.

9. Aquarius was featured in the comic strip Sherman’s Lagoon in 2012.

10. The Hab was originally built in Texas.

10 Fun Facts: Coral

1. Reefs usually grow up on the east shore of land masses.

2. Parts of a coral reef can be harvested to make medications to treat cancers and other illnesses.

3. A coral reef isn’t a single organism; it’s actually a community of life that lives and thrives in one location.

4. Only about one percent of the world’s oceans contain coral reefs. That’s about the size of France.

5. Coral reefs are the largest biological structures on earth.

6. Corals are related to jellyfish and anemones.

7. There are over 2,500 species of corals. About 1,000 are the hard corals that build coral reefs.

8. Reefs grow where there are stronger wave patterns and currents to deliver food and nutrients.

9. The Great Barrier Reef is 500,000 years old.

10. Most coral reefs grow just about two centimeters per year.

10. Most coral reefs grow just about two centimeters per year.

10 Fun Facts: Invasive Species

1. To be considered invasive, a species must adapt to a new area easily. It must reproduce quickly. It must harm property, the economy, or the native plants and animals of the region.

2. Some invasive species are introduced accidentally, but others are brought deliberately.

3. Ship ballast water transports between 3,000 and 7,000 foreign species daily around the globe.

4. The total loss to the world economy as a result of invasive non-native species has been estimated at 5% of annual production

5. Invasive species have contributed to 40% of the animal extinctions that have occurred in the last 400 years.

6. Rodents are some of the worst invasive species.

7. There are an estimated 50,000 wild ring-necked parakeets in parks across London and southeast England.

8. Black and Norway rats annually consume stored grains and destroy other property valued over $19 billion.

9. Northern Pacific seastars reproduce very quickly. In one area where they were introduced, their population reached an estimated 12 million seastars in just two years.

10. Starlings were introduced to New York in the late 1800s, as part of an attempt to bring animals that were mentioned in Shakespeare‘s work to America.

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