What are the various systems that make the human body?

How do they work together to make us... human?

And how can we organize our understanding of the various systems and how they fit together?

We love this video from National Geographic for the crisp way in which it organizes the many different systems of the body into three larger categories. What happens when you structure lots of smaller pieces of information into categories -- does it make it easier or harder to remember them? And is it more or less overwhelming?

Here are some of the things we've learned about how the body rules the brain and the brain rules the body:

Examples from the Cardiovascular system:

• There are cells in the heart that perceive how fast it's beating and send those signals to the brain. Sometimes when our heart beats quickly, it makes us feel anxious, but other times, like when we're exercising, it can make us feel better.

• Sometimes when something jumps out at you, it triggers your emergency response system, with an automatic response of fear, creating a reaction of fight, flight or freeze. Your brain then triggers your sympathetic nervous system, preparing your body to move away to ensure your survival! When this happens, it triggers your heart to beat faster and your arms and legs to get ready to run. But if nothing happens, as might happen when the thing that scared you was a horror movie, your body will come down again until the next scare.

• Sometimes, this can happen just because your brain is thinking about things that make us feel anxious or scared, so we can learn to control our sympathetic nervous system to calm it down again. For example, when we take a deep breath, we mimic the way the body functions when it feels safe, which in turn sends signals to the brain that help us to feel calmer. So once we understand how our sympathetic nervous system works, we don't have to be at its mercy!

Muscles:

• Your proprioception is felt between the joints and your muscles. The input into those joints release dopamine.

• In freeze, fight, flight mode, our heart pumps more blood to our muscles have increased strength.

• The cerebellum coordinates balance, movement and coordination.

Digestive system:

• The brain organizes the body to move when we need to go to the bathroom, and the digestive system sends signals to the brain when it needs to go to the bathroom!

• The foods we eat can affect how the brain functions. Carbohydrates gives us energy but they can make them really hyper

• Sometimes, we have a really bad experience at the same time that we happen to be eating something, and our brain remembers that food as being responsible for it.

Immune system:

Nervous system:

• When something scary happens (physically or emotionally), our body goes into freeze, fight, flight and our sympathetic nervous system tells our body what to do.

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