Video Watching

    Watch a video clip and do the exercise.

Preparation

Script:

I tell you, working in a place like this, you can sure learn a lot about muscles.Hah. I mean sure there are three different types of muscles: cardiac, smooth,and skeletal. And skeletal is the only type you can see but what you can’t see?Pretty impressive. Hey, thanks, Rex.

There are three fundamental types of muscle tissue: cardiac, smooth and skeletal. Cardiac muscle forms the walls of the heart and contracts to propel blood through the blood vessels of the body. Cardiac muscles are involuntary. Involuntary musclesare muscles we have no conscious control over. Cardiac muscles are striated,which means the muscle tissue has obvious stripes or striations.

Smooth muscle forms the walls of hollow structures like the digestive tract. It’s also responsible for changing the diameter of these tubes to move stuff like food through them. Smooth muscle is controlled by the autonomic nervous system. Basically that means the smooth muscle works without any conscious help from us. It’s on autopilot. Smooth muscle cells are unstriated. That means they don’t have the stripes that cardiac and skeletal muscles have, but like cardiac muscles, smooth muscles are involuntary. We can’t control them consciously.

Skeletal muscles, the final division, are typically attached to the skeletal system,hence the cover name—skeletal muscles.

The skeletal muscles are also responsible for body movements and facial expressions. Throwing balls, running from the police, frowning in disgust, allthese things are the bread and butter of skeletal muscles.

Skeletal muscle cells are elongated, striated and under voluntary control.

Sowhen you think skeletal muscles, think striated and voluntary. Apart from movement,skeletal muscles have a number of other responsibilities. Skeletal muscles help you stand. They maintain posture by resisting the pull of gravity.

Nothing can resist the downward pull of gravity. Just watch! Hah! It's impossible, I tell you.