MAIN Health The Human Body Muscles

Got muscle?

The human body contains more than 600 muscles that do everything from pump blood (like the heart muscle) to the heavy lifting performed by the muscles in our legs, arms and shoulders.

Some muscles move only when we say so, set off by electrochemical impulses from the brain and nervous system.

These impulses stimulate fibers called sarcomeres, causing them to shorten. Contraction continues until the impulses cease and the muscle once again relaxes.

But muscles aren't only about individual movement, strength and physical prowess.

Some muscles — like cardiac muscle and smooth intestinal muscle — perform what are called involuntary muscle movements. They are responsible for the beating of the heart and digestion of food.

If we had to consciously control all these involuntary muscle movments it would make life rather difficult ...and sleeping next to impossible.

Skeletal muscle

The major kind of muscle is skeletal muscle, which is the muscle anchored to our bones that helps us move our bodies. Skeletal muscle is further divided in to two different categories, the fast twitch muscle and the slow twitch muscle.

Fast twitch muscles, like the hamstring, help us to perform fast movements such as power walking and sprinting. The downside of this type of skeletal muscle is that it doesn't get a lot of blood, and so tires out easily.

The other kind of skeletal muscle (like those found in the back and lower legs) is the slow twitch muscle. This muscle type gets a lot of blood and oxygen necessary to perform extended aerobic activities that fast twitch muscles just can't support.

The human body is made up of an equal number of of fast and slow twitch muscles, which is why athletes include both types of muscle conditioning in their training regimes.

Keeping muscles fit

Besides getting plenty of oxygen to muscles, there are other things you can do to help keep your muscles performing better.

When people think about ways to keep their muscles healthy, most think of exercise. And although running and jogging, or working out at the gym is important, muscles — like every other organ in the human body — are also largely dependent on good nutrition.

Special sports drinks, or extra carbs before a big competition may fuel extra muscle performance, but most people simply need to make a daily habit of maintaining a proper diet. This means less sugary and fatty foods, lots of fresh fruits and vegetables, and drinking plenty of water to keep the muscles limber and strong.

More about human anatomy and muscles around the Web:

Functional Anatomy of Skeletal Muscles - Interactive tutorials on how they work and their location on the body with Flash animations, quizzes.

Muscle Atlas - Comprehensive resource from the University of Washington with information on every muscle in the human body, their location and function, with related photos and illustrations.

Muscular system - Detailed overview of skeletal, smooth, and cardiac muscles with related illustrations, including a discussion on muscle contraction and how bones and muscles interact.

Your Gross and Cool Body - Muscular System - Kid-friendly information on different types of muscles, what they do and how they move.

also see in Pain -> Muscle Pain