Some muscles work without you ever thinking about them. Smooth muscle cells quietly squeeze your food along and help control your blood tubes.
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Smooth muscle cells are long and thin with pointy ends, a bit like a stretched-out lemon. Each one has one nucleus in the middle.
They have no stripes. That's why they are called smooth!
They line up side by side in sheets, wrapped around tubes in your body.
Press Squeeze on the 3D model to see the cells get shorter and fatter.
Smooth muscle is involuntary. That means it works on its own.
When you get goosebumps, tiny smooth muscles are pulling your hairs up straight!
Home activity: Sit in a dim room for a minute with a mirror. Then turn on the room light and watch your eyes. The black dot in the middle, your pupil, gets smaller! Smooth muscle in your eye did that all by itself.
Smooth muscles squeeze slowly, but they can keep going for a long time without getting tired.
Food can take a day or more to travel all the way through you, pushed along by smooth muscle the whole time.
By learning junction. A fun video for kids.
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