The Skeleton and Movement Chapter 8

The Skeleton The skeleton forms the framework of your body. Gives your body shape and holds your body upright.

The Skeleton 2 types of skeleton: Exoskeleton: skeleton on the outside of their body i.e. A crab. Endoskeleton: Skeleton on the inside of their body i.e. A Human

Functions The three functions of the skeleton are: Support Protection Gives the body its shape Protection Protects important organs i.e. The Brain Movement Works along with the muscles for movement.

Bone Structure Bone is made of living cells. Living cells release calcium compounds which make the non living part of the bone. The non living part of the bone forms a hard, rigid framework around the bone.

Joints Joints are formed where two bones meet. There are 2 types of joints: Fused joints (Immovable) Freely moving or Synovial joints (moveable)

Fused Joints Fused joints have no movement between the bones. Also called fixed or immovable joints. Example: The Skull

Synovial Joints Moveable joints usually contain a fluid called Synovial fluid. Synovial fluid acts as an oil and allows the joint to move more freely. 2 types of moveable joint: Hinge Joint Ball and Socket Joint

Hinge Joint A hinge joint allows movement in one direction only. Example: The Elbow

Hinge Joint Ligament Synovial Fluid Cartilage

Ball and Socket Joint A ball and socket joint allows movement in all directions. Example: The Shoulder

Ball and Socket Joint Ligament Cartilage Synovial Fluid

Functions Cartilage – Cushions the bone and acts as a shock absorber. Synovial Fluid – Acts as a lubricating fluid between the bones. Both cartilage and synovial fluid prevent friction between the joints

Ligaments: Join bone to bone. Tendons: Join muscle to bone.

Antagonistic Pair Muscles work by either contracting or relaxing. Muscles cannot push. This means muscles work in pairs called antagonistic pair.

Example: The Arm There is 2 muscles in the upper arm the biceps and the triceps. To raise the arm the