In the tiny town of Beatingburg, muscles were not all the same. One special type, Cardy, was different. He was a cardiac muscle!
Cardy worked in the heart's walls. His job was to pump blood every day without rest, keeping everyone in the town healthy.
Unlike other muscles in Muscleland, Cardy and his friends could not tire. They had mighty power from tiny energy houses called mitochondria.
Cardy was special because he could beat on his own, without a signal from the brain. This was his superpower, called automaticity.
Cardy explained to the curious student muscles, 'We work together, contracting in perfect harmony. It's called syncytium!'
In times of danger, when an evil blockage threatened the flow, Cardy and friends worked harder, showing incredible endurance.
The student muscles asked, 'How do you beat stronger when we need more oxygen?' 'Ah,' said Cardy, 'that’s the Frank-Starling law at work!'
One day, a student named Fibby asked, 'Do we all grow the same?' Cardy shook his head. 'We only grow bigger, not in number.'
Cardy was proud of his responsibility. 'Even though we are involuntary muscles, we keep Beatingburg alive with every beat!' he exclaimed.
Fibby wondered aloud, 'How do you stay so strong?' 'Exercise!' chuckled Cardy. 'And a good diet helps keep us all thumping healthily.'
As the moon rose over Beatingburg, the muscles settled down. 'Remember,' whispered Cardy, 'we're strong because we beat as one.'
And with that thought, the muscles of Muscleland felt proud, promising to keep Beatingburg beating through the power of their heart.
Reflection Questions