Muscles

• Arm muscles like triceps, biceps etc.
• Leg muscles like thigh, shin etc.
• Upper muscles like neck, shoulder etc.

Muscles are attached to bones by tendons. Muscles are arranged in pairs called antagonistic pairs. Muscles work by contracting and relaxing. They cannot push. When the muscles contracts, it pulls on the bone. At the same time, the other muscle in the pair relaxes. The pull of the contrasting muscle will cause movement to occur at the joint.

Muscles are a type of tissue - lots of muscle cells work together to cause movement. Muscles can only pull - the work together by getting shorter (contract). Muscles are attached to bones by tendons. When a muscle contracts, it pulls on a bone. If the bone is part of a joint, the bone will move.

Here are some types of muscles in the human body, followed by its functions:

• neck muscles - hold the head up and move it in all directions
• shoulder muscles - raise and lower the arms
• triceps - straighten the arm
• biceps - bend the arm
• abdominal muscles - move the torso and help with breathing
• thigh muscles - move the lower leg
• calf muscles - pull the heel up and point the toes
• shin muscles - help move the foot up and down and side to side

How do muscles work to bend and straighten the arm?

To bend the arm:

• Biceps muscle (front of the arm) contracts
• Triceps muscle relaxes
• Tendons of the biceps are attached to the radius. This allows the biceps to pull the lower arm up.

To straighten the arm:

• Biceps muscle relaxes
• Triceps muscle contracts
• Triceps pulls at the back of the elbow.