Bone, Cartilage and the Mechanics of a Joint · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Living bone and clever joints

Science · The Human Body · ages 19-20
Name ______________________   Date ____________

  1. What does cartilage do inside a joint?

    • Coats surfaces, absorbs shock, and lets bones glide
    • Pumps blood cells
    • Ties muscle to bone

  2. Why does a broken bone heal?

    • Bone is dead mineral and cannot change
    • Bone is living tissue that rebuilds
    • Cartilage turns into plaster

  3. A cord ties a muscle to a bone across the elbow. What is it?

    • A ligament
    • Cartilage
    • A tendon

  4. An astronaut returns with thinner leg bones after months in zero gravity. Why?

    • Unloaded bone tips the rebuild balance toward removal
    • Space dissolves calcium directly
    • Muscles ate the bone

  5. A joint swings widely in many directions. What shape fits best?

    • A hinge
    • A ball and socket
    • Flat gliding faces

  6. A muscle pulls 4 cm from a joint while the load hangs 20 cm out. To balance turning effects, the muscle force must be?

    • Smaller than the load
    • Equal to the load
    • Larger than the load

  7. A student works out a muscle force by adding load and pull. What is the error?

    • Muscles cannot pull
    • Lever forces balance as turning effects, not as a simple sum
    • Loads have no turning effect

  8. Strong hip ligaments give the hip a wider range than the shoulder.

    Circle one:   True   False

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Answer key

For grown-ups. Fold this page away before handing over the rest.

Living bone and clever joints W1-mt_1_q3aL7E5D-s1

  1. Coats surfaces, absorbs shock, and lets bones glide · Cartilage coats, cushions, and slicks the gliding surfaces.
  2. Bone is living tissue that rebuilds · Living bone constantly rebuilds, so it can knit a fracture.
  3. A tendon · Muscle to bone straps are tendons; bone to bone are ligaments.
  4. Unloaded bone tips the rebuild balance toward removal · Without load the removers outpace the builders.
  5. A ball and socket · Only the ball and socket offers wide multi direction swings.
  6. Larger than the load · The short muscle arm must pull harder to match the long load arm.
  7. Lever forces balance as turning effects, not as a simple sum · Lever balance compares force times arm on each side.
  8. False · Hip ligaments trade range for stability, so the shoulder ranges wider.
Worksheet · LightMySky