1. A tendon is a tough band of fibrous connective tissue that connects muscle to bone.
2. An extensor is a muscle that straightens a joint or extends a body part.
3. A flexor is a muscle that bends a joint or flexes a body part.
4. There are about 600 muscles in the human body.
5. Tendons connect muscle to bone; ligaments connect bone to bone.
6. Muscles must contract (shorten) and relax to move a bone.
7. Muscles work together in pairs or groups — when one contracts, the other relaxes, allowing controlled movement around joints.
8. The biceps muscle of the arm is a flexor.
9. The triceps muscle of the arm is an extensor.
10. Muscles are attached to bones and contract (shorten) to pull on bones, causing movement at the joints.
Skill Challenge:
2. The triceps is actually a group of three muscles because this arrangement allows for greater strength and control when extending the elbow. Multiple heads provide more attachment points and force distribution, enabling powerful and precise movements.
3. Ball-and-socket joints (like shoulder and hip) require a team of many muscles to provide movement in all directions. This is because multiple muscles are needed to stabilize the joint while allowing movement across multiple planes — flexion/extension, abduction/adduction, and rotation — which single muscles cannot achieve alone.
Parent Tip: Review the logic above to help your child master the concept of muscular system worksheet pdf.
