DEDICATION

Dear Ms. Walling, I hope you enjoy reading this short story. Doing this book has really helped me understand the fundamentals of muscle contraction.

Hi, Im McQueen the Muscle messenger! When your brain says "Move!" I race down the body's signal highway to tell your muscles what to do.

        Neuron Road

That's my cue! I grab an action potential and shoot down my motor neuron to start the journey.

Time to wave hello!

    The Brain Sends a Signal

Whoosh! I'm flying through my axon, carrying the signal toward the neuromuscular junction- the special meeting place between neuron and muscle.

    Zooming down the Axon    

Arrival at the junction

We've reached the end of the axon where there are tiny vesicles full of a messenger chemical called acetylcholine (ACH). They're ready to deliver their message.

Hi! We are Vesicles full of ACH!

        Message Launch

The vesicles burst and release ACh into the synaptic cleft. The signal flies towards the muscles motor end plate.

Hello we are ACh!

ACh Delivers the News

ACh binds the receptors on the sarcolemma (muscle's outer layer).

Now sodium ions (Na+) rush in and potassium ions  (K+) rush out- this is DEPOLARIZATION

Hello! Im a receptor with NA+ and K+ Ions

Take me with you!

            The Signal Spreads

The motor end plate potential races across the sarcolemma, spreading the signal all around the muscle fiber.

KACHOW!

    Into the T-Tubules 

The message dives through tunnels called the T-Tubules (transverse tubules) so every part of the muscle hears the call.

HOWDY YALL!

    Wake Up Calcium Crew!    

Inside the sarcoplasmic reticulum, voltage sensitive calcium channels pop open. Calcium ions (Ca^2+) rush out, ready to work!

Lets Get to Work!

Im ready!

The Calcium Connection

Calcium sticks to troponin, which moves tropomyosin out the way.

Now the actin sites are open and ready!

Come with me!

See ya later!

Meet Actin and Myosin

Inside each sarcomere, actin and myosin get ready to team up.

This teamwork is called the sliding filament.

Team work makes the dreamwrork!

The Cross-Bridge Crew 

Myosin heads grab onto actin, forming cross-bridges.

Teamwork power Activate!

LETS GO!