Lesson focus: A synovial jointA joint that moves freely, like the knee, with liquid inside to stop the bones rubbing. permits movement while reducing friction and maintaining stability.
Explain roles of cartilageSmooth, slightly bendy tissue that covers the ends of bones at joints., synovial fluidAn oily liquid inside a joint that helps the bones move smoothly., capsule, ligamentA strong band of tissue that holds two bones together at a joint. and tendonA strong cord of tissue that joins a muscle to a bone..
Build on earlier learning
SkeletonUse bone and lever ideas to understand movement at joints.
You will be successful when you can…
- Label a synovial joint.
- Distinguish ligament from tendon.
- Explain cartilage and fluid roles.
- Predict effects of specific injuries.
Words that carry the science
- synovial joint
- Freely movable joint with a fluid-filled cavity.
- cartilage
- Smooth resilient tissue covering bone ends.
- synovial fluid
- Lubricating fluid within the joint cavity.
- ligament
- Strong band connecting bone to bone.
- tendon
- Strong tissue connecting muscle to bone.
Balance movement, friction and stability at a joint
01Reduce friction at moving surfaces
Articular cartilageSmooth, slightly bendy tissue that covers the ends of bones at joints. covers bone ends, reducing friction and absorbing shock. synovial fluidAn oily liquid inside a joint that helps the bones move smoothly. lubricates surfaces inside the capsule.
The capsule encloses the cavity and contributes stability. In short: cartilageSmooth, slightly bendy tissue that covers the ends of bones at joints. is a smooth, slippery layer on the ends of bones, so they do not rub. synovial fluidAn oily liquid inside a joint that helps the bones move smoothly. is an oily liquid that helps the joint move smoothly.
02Connections have different jobs
A ligamentA strong band of tissue that holds two bones together at a joint. connects bone to bone and limits excessive movement. A tendonA strong cord of tissue that joins a muscle to a bone. connects muscle to bone and transmits pulling force.
03Shape affects movement
Ball-and-socket joints permit movement in many directions; hinge joints mainly move in one plane. Greater mobility can require strong stabilising structures.
Joints and movement
Where two bones meet there is a joint. A hinge joint moves one way like a door; a ball and socket joint moves in every direction; a fixed joint does not move. Muscles pull on the bones to move them.
Controls
Cartilage covers the bone ends and synovial fluid lubricates the joint, so the bones do not rub. Ligaments hold the bones together.
Diagnose two injuries
Compare a torn ligament with a torn tendon at the knee.
- Ligament: bone-to-bone connection is damaged.
- Prediction: joint stability may fall or movement may become excessive.
- Tendon: muscle-to-bone force pathway is damaged.
- Prediction: the muscle may contract but move the bone less effectively.
How to make the reasoning visible: Use the structure’s actual connection to predict the functional effect.
Joint-structure cards
Match each structure to connection and effect.
| Structure | Connection/location | Effect |
|---|---|---|
| Cartilage | Covers bone ends | Reduces friction; absorbs shock |
| Synovial fluid | Inside joint cavity | Lubricates surfaces |
| Ligament | Bone to bone | Stabilises and limits excessive movement |
| Tendon | Muscle to bone | Transfers pulling force |
Why can ligament damage make a joint unstable?
Why would a tendon injury affect movement differently?
Use the table. Compare a ligament and a tendon.
Check your understanding
Answer from memory, then check against the suggested answer.
What connects bone to bone?
What connects muscle to bone?
What lubricates a synovial joint?
What does cartilage do?
Name one example of a hinge joint.
Predict one effect of worn cartilage.
Why might a very mobile joint be less inherently stable?
The shoulder can move in many directions but the elbow mainly moves one way. Name each joint type.
Exam Question Practice
Exam Question Practice
Mark points shown after marking
A joint is where two bones meet. Answer the parts to explain how its parts help it move safely.
What covers the ends of the bones? What does it stop?
(1)What liquid is in the joint? What does it do?
(1)What joins bone to bone?
(1)What joins muscle to bone?
(1)Total for this question: 4 marks
Command word: Name each part and say what it does.