EVERYDAY SCIENCE

SCIENCE

SKELETAL SYSTEM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
How do pairs of skeletal muscles work together?
A
Both muscles contract at the same time
B
Both muscles extend at the same time.
C
While one muscle in the pair contracts, the other returns to its original length
D
One muscle in the pair pulls on a bone, while the second muscle pulls on the first muscle
Explanation: 

Detailed explanation-1: -Muscles can pull bones, but they can’t push them back to the original position. So they work in pairs of flexors and extensors. The flexor contracts to bend a limb at a joint. Then, when the movement is completed, the flexor relaxes and the extensor contracts to extend or straighten the limb at the same joint.

Detailed explanation-2: -Muscles work in pairs, when one muscle shortens the opposite muscle lengthens e.g. the biceps shortens to bend the elbow at the same time its opposite muscle, the triceps, lengthens to allow the movement to occur. Good working between pairs of muscle allows for smooth controlled movement.

Detailed explanation-3: -Skeletal muscles only pull in one direction. For this reason they always come in pairs. When one muscle in a pair contracts, to bend a joint for example, its counterpart then contracts and pulls in the opposite direction to straighten the joint out again.

Detailed explanation-4: -Your muscle fibers contract (tense up) in response to the message. When the muscle activates or bunches up, it pulls on the tendon. Tendons attach muscles to bones. The tendon pulls the bone, making it move.

Detailed explanation-5: -When one of them contracts, the bone is pulled in that direction and the other muscle of the pair relaxes. To move the bone in the opposite direction, the relaxed muscle contracts and the first one relaxes. Thus two muscles have to work together to move a bone.

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