SCS.B | The Anatomy of Sleep |

SCS.B | The Anatomy of Sleep

Sleep! No, wait! That wasn’t a command, it’s what we’re talking about in this Hab Lesson!

More specifically, we’re going to talk about sleep, or rather the lack thereof, in extreme environments like the Hab and the International Space Station. But first, let’s talk about what sleep is.

What is Sleep?

The funny thing is that, even though you’ll spend about a third of your life doing it, scientists still aren’t exactly sure why we sleep. Sleep is important to a number of brain functions, including how nerve cells (neurons) communicate with each other. In fact, your brain and body stay remarkably active while you sleep. Recent findings suggest that sleep plays a housekeeping role that removes toxins in your brain that build up while you are awake.

Everyone needs sleep, but its biological purpose remains a mystery. Sleep affects almost every type of tissue and system in the body, from the brain, heart, and lungs, to metabolism, immune function, mood, and disease resistance. Research shows that a chronic lack of sleep, or getting poor quality sleep, increases the risk of disorders including high blood pressure, cardiovascular disease, diabetes, depression, and obesity.

Your brain is an incredibly complex organ–it has to be, since it regulates all of the functions of the rest of your body–so there is a lot going on inside your skull while you’re sleeping. Here’s some of what’s going on in there:

As I just mentioned, your brain is incredibly complex and what you may not know is that the brain is not just a single organ, but a whole collection of parts that regulate your body and how you process information coming in from the outside world. Here’s how that complex system handles your sleep.

Bits o’ Brain

Hypothalamus

The hypothalamus is a peanut-sized structure deep inside the brain that contains groups of nerve cells that act as control centres affecting sleep and arousal. Inside, there are clusters of cells that receive information about light exposure directly into the eyes. This structure controls your behavioural rhythm.

Brain Stem

Down at the base of the brain is the brain stem, which communicates with the hypothalamus to control the transition between wakefulness and sleep. The brain stem (especially the pons and medulla) also plays a special role in REM sleep; it sends signals to relax muscles so that we don’t act out our dreams.

Thalamus

Another organ that helps regulate your sleep is the thalamus, which acts as a relay for information from the senses to the cerebral cortex (the covering of the brain that interprets and processes information from short- to long-term memory). During most stages of sleep, the thalamus becomes quiet, letting you tune out the external world. But during REM sleep, the thalamus is active, sending the cortex images, sounds, and other sensations that fill our dreams.

Pineal Gland

The pineal gland, located within the brain’s two hemispheres, helps put you to sleep once the lights go down. It does this as receives signals from the SCN and increases production of the hormone melatonin. Scientists believe that peaks and valleys of melatonin over time are important for matching the body’s circadian rhythm to the external cycle of light and darkness.

The basal forebrain, near the front and bottom of the brain, also promotes sleep and wakefulness, while part of the midbrain acts as an arousal system. Release of adenosine (a chemical by-product of cellular energy consumption) from cells in the basal forebrain and probably other regions supports your sleep drive.

Amygdala

Last, we’ve got the amygdala, an almond-shaped structure involved in processing emotions, becomes increasingly active during REM sleep. So, you know when you become happy when something good happens in a dream, or you become frightened during a nightmare? Thank your amygdala.

The brain is a complex place, even when all you’re doing is sleeping. You might think of sleep as just one thing, but that’s also a complicated process, with different things going on at different stages.

Curriculum Reference Links

Biological World / Building Blocks / 1: Students should be able to investigate the structures of animal and plant cells and relate them to their functions

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.

Previous Lesson

Next Lesson