Heart Muscle Cells

Striped and branching

Heart muscle cells are only found in your heart. They are a special kind of muscle cell.

• They have stripes, like the muscles in your arms and legs.
• They are short and branch like the letter Y.
• They are joined end to end, so they make a big web of cells.

The joints between them let a squeeze signal zip from one cell to the next.

They beat all by themselves

You don't have to think to make your heart beat. A small group of special pacemaker cells sends a signal, and the heart muscle cells squeeze together.

Each squeeze pushes blood out of your heart and around your body. Then the cells relax and the heart fills up again.

Helping your heart

Heart muscle gets stronger when you are active. Running, jumping, dancing, and playing tag are all great for your heart.

Home activity: Gently press two fingers on the inside of your wrist, below your thumb. Count the beats for 15 seconds, then times by 4. Now jump in place 20 times and count again. Your heart speeds up to send more blood to your busy muscles!

Heart muscle quiz