OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

How does synovial fluid function in a joint?

1. Protects the bone structure

2. Lubricates the joint to reduce friction

3. Facilitates bone growth

4. Enhances muscle movement

The correct answer is: Lubricates the joint to reduce friction

Synovial fluid plays a crucial role in joint health and function primarily by lubricating the joint. This lubrication minimizes friction between the articulating surfaces of the bones during movement, which is essential for smooth and pain-free motion. The fluid coats the cartilage surfaces, allowing them to glide against each other without causing wear or damage, thus preserving joint integrity over time. Without adequate lubrication from synovial fluid, joints would undergo increased friction, leading to damage of the cartilage and potentially resulting in conditions such as arthritis. This protective measure is particularly important during physical activities that involve repetitive movements. While synovial fluid contributes to overall joint health, it does not directly protect bone structure or facilitate bone growth. It also does not enhance muscle movement, as those functions are primarily related to muscle contraction and motor control.