strong heart
In the picture above, a student is squeezing a tennis ball once every second to simulate how hard the heart works to pump blood through your body. It might not seem hard, but after a few squeezes, your arm is burning from the effort. This is what your heart has to do 24/7, from the day you are born to the day you die.
one-sided
Most muscles are attached to other things on both ends. The only exception to this rule is the tongue. Believe it or not, the tongue is actually a large, exposed muscle only attached to your body at one point. That's why your tongue is able to move without bones and joints. Muscles are built for movement, so of course the tongue can move without bones.
sextuplets
There are lots of subdivisions in the muscle family. Plenty of uncommon types of muscle are out there, but there are six major types that really stand out. They are parallel muscle, circular muscle, convergent muscle, unipennate muscle, multipennate muscle, and bipennate muscle.
smooth!
A special type of involuntary muscle, called smooth muscle, inhabits the hollow places in your body. It can be found in your bladder, blood vessels, intestines, and stomach.
most used
The most used muscle in the human body isn't the tongue or facial muscles. It's actually the heart, the reason being that facial muscles can relax, while the heart is an involuntary muscle and therefore beats all the time.
the science of the buttocks
The largest muscle in the human body is the butt. It's not just a bunch of fat. It actually serves the important purpose of supporting your upper body. Without the butt, you wouldn't be able to sit up for very long. Or sit down without hurting.
it's all wrapped up
Muscles wouldn't really be able to make you move on their own. They work together with the skeletal system, pulling on bones to make you move. The muscles are attached to and tightly wrapped around the bones in your body.