DAY 26 - The Nervous System

DAY 26 -

The Nervous System

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Multiple Choice

The nervous system receives all the information from the senses and tells your body how to react to it.

• True

• False

Multiple Select

Select your three out of the five main senses in the human body:

• Touch

• Future

• Taste

• Smell

• Music

But did you know...?

The human body has more than five senses! Oh yeah!

Beyond the five we know (smell, taste, sight, touch, hearing) we have:

+ Proprioception: sense of space

+ Thermoception: sense of temperature

+ Nociception: sense of pain

+ Equilibrioception: sense of balance

Sadly, none of them make you a superhuman or a superhero.

We're still just human.

Here are two diagrams of the nervous system in the human body. One big organ (the brain) plus a bunch of "wires" that spread out all over the body and control every organ and muscle. Even more impressive--it uses electricity to work!

The Nervous System is split into parts. Each part does a special job.

Central

Nervous System

Includes:

+ the brain

+ the spinal cord

Controls most other organs, reflexes, and conscious thoughts throughout the body.

Peripheral

Nervous System

Includes:

+ ALL the nerves in the body

+ NOT the brain or spinal cord

Senses the environment, then gets orders to move muscles in the body.

It's mostly tied to the spinal cord.

Multiple Choice

The peripheral nervous system is the brain and the spinal cord.

• True

• False

Sensory vs Motor

Sensory = nerves that sense world

Motor = nerves that move body

They're controlled by the peripheral nervous system but integrated in the CNS after the fact.

Example: You feel the flame is hot, then your spine/brain tells your hand to move away to protect you.

Voluntary vs Involuntary

Voluntary = you chose to do it

Involuntary = you're forced to do it

In the example: You probably move your hand before thinking about it. It's a reflex meant to keep you safe!

Another example: Breathing!

Multiple Choice

Voluntary means that you can control how it moves.

• True

• False

Parasympathetic Nervous System

Also known as:

+ the "Fight or Flight Response"

Usually triggered when you encounter a threat or danger.

Parts of the brain activate adrenaline. It prepares your body to face down or flee from danger.

Sympathetic

Nervous System

This is most people's basic way of life--chillaxing, no stressing vibe.

Wakes up after the parasympathetic nervous system stops going overdrive.

Relaxes muscles, brings down heart beat and breathing rate, turns on the growth and healing organs.

Multiple Choice

The parasympathetic nervous system is also known as the "fight or flight" reaction.

• True

• False

Both of these systems can be affected by mental health. For example:

Stress is a parasympathetic response, whether real or not. It can stop the sympathetic (chill) nervous system from kicking in, slowing down healing and growth until serious damage is done to the body.

Now, for the cellular level!

Woot, let's talk about neurons!

Neurons are the CELLS that make up the nervous system.

Nerves are TISSUES made from neurons!

Think of it all like rope.

Threads spun together make rope.

Neurons put together make nerves!

^{(Real neurons scanned by Koch Institute.)}

Neural Anatomy

This is a typical neuron... not all look the same, some are more complex!

+ Dendrite: receive signals

+ Axon: long tail, carries signal

+ Axon Terminal: sends signal

+ Myelin Sheath: insulates signal

+ Cell Body: acts like a normal cell

Multiple Choice

Axon terminals send signals on to the next neuron.

• True

• False

Neural Synapses

Neurons are actually NOT touching!

There's a space between them called the "synapsis"

Signals have to jump that space!

They turn electrical signals into chemicals that carry the same information across the empty space, then throw chemicals across... almost like a rain storm!

Even then, brain signals are FAST!

Signals can travel at a huge speed!

The slowest are 2 miles per hour, slower than walking!

The fastest ones are up to 200 miles per hour!