How Skeletal Muscles Make the Body Move
Published By joeldgreat on 2011-05-03 626 Views
Bones are joined together to allow different kinds of movement. But did you know that, without muscles, bones cannot move at all?
Muscle-bone connection . Touch the back of your foot just above the heel. Do you feel a tough cord of tissue inside? This tough cord is the tendon that connects your calf muscle to your heel bone. Clench your fist. Do you see the tendons in your wrists? Bend and extend your fingers. Do you notice the tendons moving? The bending and extension of your fingers are controlled by the tendons. These tendons attach the muscles of your forearm to your finger bones.
Tendons are bundles of tough fibers that attach muscles to bones. One end of a tendon comes from the end of a muscle while the other end is attached to a bone. Some tendons are round while others are flat. Tendons also differ in length and thickness.
How muscles move bone . The muscles that move bones are skeletal muscles. Skeletal muscles perform different functions. Muscles move by contracting or becoming shorter. Contraction of muscles requires energy. Energy comes from food. Bend your elbow and touch the muscle in your upper arm. Does it feel hard or soft? Straighten your elbow and feel the muscle again. Does it feel the same as before? When a muscle feels hard, it is contracted when it feels soft, it is relaxed.
How muscles makes the arm move . To bend the elbow, the biceps muscles contracts while the triceps muscle relaxes. The contraction of the biceps muscle pulls the lower arm bone upward. To straighten the elbow, the same muscles work but in the opposite way the biceps relaxes while the triceps contracts to pull the arm bone down.
The forearm can turn 180 degree without turning the upper arm. The two bones in the forearm are alongside each other. When the muscles of the forearm contract, the hand and forearm turn so that the palm faces downward. This time, the position of the bones are changed. Instead of being alongside each other, the radius now crosses over the ulna.
Skeletal muscles work in pairs . When one muscle contracts, the other relaxes. Muscles always pull. They never push. We can move our body in different ways while we work or play. In all these movements, our bones and muscles move in a coordinated way.
Here are other skeletal muscles and the work they do.
1.Muscles in the head are used for talking, moving the eyes, making facial expressions and chewing.
2.Muscles in the neck move the head and keep it upright.
3.Shoulder muscles lift the arm.
4.Chest muscles pull the arm forward and across the body.
5.Thigh muscles raise and lower the leg. They also bend and straighten the knee.
6.Muscles of the leg control the movement of the ankle, foot and toes.
note: originally posted at Exposeknowledge.com under the same author.