Ch. 11 pg 290

The movement in humans involves bones, ligaments, muscles, tendons and nerves.

 Provide anchorage for muscles  Act as levers, changing size and direction of forces  Provide support for the body and protection to internal organs  Blood cell formation  Metabolism of calcium and other minerals.

 Tough cords or sheets of tissue  Connect bones together  Cover joints and connections between bones.  Flexible to allow certain movement  Almost inelastic to prevent movement outside normal range of a joint and prevent dislocation

 Attach to bones and provide forces to change position of bones and the body.  Work in antagonistic pairs

 Tough cords or straps of tissue  Connect muscles to bones  Help to anchor muscles to bone and to transmit forces generated by contraction of muscles.

 These are the points where bones meet. There are many types of joints according to their movement, ex: fixed, ball and socket, pivot and hinge joints.

 Cartilage: though, smooth tissue that covers regions of the bone. Prevents contact between bones and absorbs shocks.  Synovial lubricates the joint and helps to prevent friction  Capsule: though ligamentous covering to the joint. Seals the joint, holds the synovial fluid and prevents dislocation.  Biceps and triceps: muscles connected to the humerus.

 Muscle used for movement – skeletal muscle.  Other types of muscle are smooth and cardiac.  Striated muscle is composed of bundles and muscle fibres  A sarcolema surrounds each muscle fibre

 Within each muscle fibre, there are many parallel elongated structures called myofibrils.  Between each myofibril are large numbers of mitochondria  Each muscle fibre contains many nuclei and a specialized E. R. called sarcoplasmic reticulum.

 Myofibrils consist of an alternating series of light and dark bands. In the center of each light band is a disk-shaped structure called the Z line. A part between one Z line and the other is called a sarcomere, the functional unit of a myofibril

 Two filaments compose myofibrils: thin actin and thick myosin filaments.  Actin filaments are attached to the Z line.  Myosin filaments are between actin filaments in the center of the sarcomere.  One myosin filament is surrounded by six actin filaments.  Together they form cross bridges during contraction shortening the length of the muscle fibre.

 During relaxation, a regulatory protein blocks the binding sites on actin.  When a motor neuron sends a signal to a muscle fibre, the sarcoplasmic reticulum releases Ca +2 that cause the regulatory protein to move.  Myosin cross bridges attach to the actin myofilament.

 Energy stored in the myosin head causes it to move inwards towards the center of the sarcomere, moving the actin filament a small distance.

 ATP causes the breaking of the cross- bridges by attaching to the myosin heads

 Hydrolysis of ATP provides energy for the myosin heads to move away from the center of the sarcomere (cocking of the m. head)  The process continues until the motor neuron stops sending signals to the muscle fibre.

 What is the role of ligaments in the elbow joint? A. Attach biceps to radius B.Reduce friction between humerus, ulna and radius C.Hold humerus, ulna and radius in proper alignment D.Secrete synovial fluid

The diagram below shows part of a muscle fibre. What parts are labelled I and II?

The unit between one Z-line and the next is termed: A. Sarcomere B. Myofibril C. Sarcoplasmic reticulum D. Sarcolemma

 Distinguish between each of the following word pairs:  Hinge joint and pivot joint  Radius and humerus  Hip and knee joint  Actin and myosin  ADP and ATP  Ligament and tendon  Extension and flexion

THE END…