Muscles and Movement
1. Describe the structure of a muscle fibre and explain the differences between fast and slow twitch fibres
- Antagonistic pairs of muscles pull in opposite directions
- Extensor muscles contract to cause joint extension.
- Flexor muscles contract to reverse the movement of the extensor muscles.
- Muscles bring about movement at a joint.
- Tendons join the muscle to the bone.
- The muscle is attached to the bone by tendons, and is on the outside of the joint.
- The ligament is on the inner side of the muscle and attaches bone to bone. It is strong and flexible.
- The fibrous capsule encloses the joint and is between the ligament and the synovial membrane.
- The synovial membrane is protected by the fibrous capsule and secretes synovial fluid.
- Synovial fluid is secreted by the synovial membrane and acts as a lubricant for the joint.
- Cartilage protects the bones within the joints and absorbs synovial fluid as well as acting as a shock absorber.
- Cartilage pads give additional protection.
- Bundles of muscle fibres make up muscles.
- Myofibrils make up muscle fibres.
- Myofibrils are made up of contractile units known as sarcomeres.
- Sarcomeres are made from thin filaments (actin) and thicker filaments (myosin).
- In contraction, the actin…