·40 % of your body weight is muscle!

·You have over 30 facial muscles which

create looks like surprise, happiness,

sadness, and frowning.

·Eye muscles are the busiest muscles in

the body. Scientists estimate they may

move more than 100,000 times a day!

·The largest muscle in the body is the

gluteus maximus muscle in the buttocks.M

uscles

Muscle Types

CardiacSmooth Skeletal

CardiacCardiac muscles are involuntary and found only in the heart. They are controlled by the brain, which controls involuntary action throughout your body.

Think about how horrible it would be to have to consciously tell your heart to beat, with the consequence of forgetting being death. What about when you went to sleep!?!

But luckily enough, the brain does all that for us.

Your heart cells come in long strips, each containing a single nucleus. Its main function is to propel blood into circulation.

Smooth

Your smooth muscles, like your cardiovascular muscles, are involuntary. They make up your internal organs, such as your stomach, throat, small intestine, and all the others, except your heart.

Unlike cardiovascular muscles, smooth muscles are generally spherical, as most other human cells are, and each contains one nucleus.

SkeletalThe skeletal muscles are the only voluntary muscles of your body, and make up what we call the muscular system. They are all the muscles that move your bones and show external movement.

Unlike either of the other two classes, skeletal muscles contain multiple nuclei, because of its large size. They are in strips up to a couple of feet long.

You have over 600 skeletal muscles.

Your muscles work with your bones

Try this. Put your elbow on the table and lift a book. Move it in all directions.

Your elbow is life a fulcrum and your arm a lever. You can move the book because of muscle contractions.

Skeletal muscles can't expand, or make themselves longer, but they can contract, or make themselves shorter, so they generally work in pairs. One contracts, and in doing so stretches the other, and reverses its effects on the joint.

For example, when you contract your major arm muscle, which is called the bicep, in return the lower arm muscle, called the tricep, extends. So as you contract one muscle the other one extends

Skeletal muscles can be broken down into groups based on their movement.

·Flexors ·Extensors ·Adductors ·Abductors

FlexorsFlexors bend at the joint. The bicep, is a flexor of the elbow joint, bringing the fist towards the shoulder.

ExtendorsOpposites of flexors,

extensors unbend at the joint, increasing the interior

angle. The tricep, is an extensor of the elbow joint, taking the fist farther away from the shoulder.

AbductorsAbductors take the

bones away from the body, like lifting the arm to the side. Spreading out your fingers uses

abductors, because you are taking away your fingers from an imaginary line running

down your arm.

AdductorsAdductors, the opposites of abductors, move toward the body. Add- means to increase or include. By lowing an arm raised to the side, or moving your fingers together while keeping them straight, your muscles are adducting.

Tendons and Ligaments

Muscles alone can't do the job. At every joint, tendons and ligaments also help out. Muscles wouldn't be very useful alone because they don't directly connect to the bone.

Muscles are connected to tendons, which are connected to the bones. When the muscles contract, they pull on the tendons, which in turn pull on the muscles, and that causes movement.

Ligaments are what hold the bones together. They connect at the ends of muscles and keep them from slipping and sliding, and force them to bend.

Hip Replacement Surgery

Bill Nye Bones and Muscles