Muscles move body parts by contracting and then relaxing. They can pull bones, but they can't push them back to their original position. So, they work in pairs of flexors and extensors. The flexor contracts to bend a limb at a joint, and the extensor contracts to straighten the limb.
For example, when you bend your elbow, the bicep muscle (the flexor) contracts, while the tricep muscle (the extensor) relaxes. When you straighten your elbow, the tricep muscle contracts, while the bicep muscle relaxes.
The brain sends signals to muscles telling them to contract or relax, which allows for voluntary movement. This process involves a complex interplay of electrical signals, chemical messengers, and protein interactions within the muscle fibers.
Here are some key points about how muscles move:
- Skeletal Muscles: These muscles are attached to bones and are responsible for voluntary movements.
- Contraction: When a muscle contracts, it shortens and pulls on the bone it's attached to.
- Relaxation: When a muscle relaxes, it lengthens and returns to its original position.
- Muscle Pairs: Muscles work in pairs to move body parts. One muscle contracts while the other relaxes.
- Nerve Impulses: The brain sends signals to muscles through nerves, causing them to contract or relax.
To summarize, muscles move by contracting and relaxing in response to signals from the brain. This process involves a complex interplay of electrical signals, chemical messengers, and protein interactions within the muscle fibers.
