The Skeletal & Muscular System (Notes)

The Skeleton, Bone and Muscles

• The functions of the skeleton are support, protection and movement.
• Muscles are attached to bones. When they contract they allow us to move.
• All vertebrates have a spine made up of vertebrae.
• Bone is a living tissue so it can grow and repair.
• The presence of calcium in bones is what makes them hard.

Joints

• Fused joints do not allow movement, eg. the bones of the skull
• Ball and socket joints allow movement in any direction, eg the shoulder and the pelvis.
• Hinge joints allow movement in one direction only, e.g. the knee.

Ligaments and Tendons

• Ligaments join bone to bone.
• Cartilage acts as a shock absorber between bones.
• Synovial fluid acts as a lubricant.
• Tendons join muscle to bone.

Antagonistic Muscles

• Antagonistic muscles are pairs of muscles that pull in opposite directions, e.g. the biceps and triceps of the arm.
• To raise the arm, the biceps contracts and the triceps relaxes. To lower the arm, the triceps contracts and the biceps relaxes.

Bones in the skeleton that you need to know

• Skull
• Shoulder Blade
• Breast Bone
• Ribs
• Vertebrae
• Pelvis
• Collar Bone
• Humerus (HL only)
• Ulna (HL only)
• Radius (HL only)
• Femur (HL only)
• Tibia (HL only)
• Fibula (HL only)