Muscles and Movement IB Biology

11.2.1 State the role of bones, ligaments, muscles, tendons and nerves in human movement.

Joints Also called articulations or arthrosis Two or more bones contact each other Provide mobility Determine the type or range of motion of a particular area of the body

Bones Are organs Provide a framework to support the body Protection of soft tissue and organs Act as levers for body movement Form blood cells in the bone marrow Allow storage of minerals – calcium and phosphorus Bone to bone connection by ligaments Strengthen joint Provide stability

Muscles and Tendons Tendons – cords of dense connective tissue Connect muscles to bone Muscles – provide force for movement by shortening the length of their fibers (cells) Muscles only move by contracting fibers Most muscles occur as antagonistic pairs

Nerves Sensory nerve endings housed in ligaments Allow for monitoring of the position of the joints Help prevent over-extension of the joint and it parts

11.2.2 Label a diagram of the human elbow joint, including cartilage, synovial fluid, joint capsule, named bones and antagonistic muscles (biceps and triceps).

Hinge joints Works like a door

11.2.3 Outline the functions of the structures in the human elbow joint named in 11.2.2

Joint Part Function Cartilage Reduces friction & absorbs compression Synovial fluid Lubricates to reduce friction & provides nutrients to the cells of the cartilage Joint capsule Surrounds the joint, encloses the synovial cavity, & unites the connecting bones Tendons Attach muscle to bone Ligaments Connect bone to bone Biceps muscle Contracts to bring about flexions of the arm (reduce an angle) Triceps muscle Contracts to cause extension of the arm (increase an angle) Humerus Acts as a lever that allows anchorage of the muscles of the elbow Radius Acts as a lever for the biceps muscle Ulna Acts as a lever for the triceps muscle

11.2..4 Compare the movements of the hip joint and the knee joint

Ball and Socket Joints The hip is ball and socket joint Permits movement in several directions, including rotational movement Head of femur (ball) fits into acetabulum (depression) of the hip

Hinge Joints Provides an opening-and-closing type of movement like the action of a door

Comparing hip & knee joints Hip Joint Knee Joint Freely moveable Angular motions in many directions and rotational movements Angular motion in one direction Motions possible are flexion, extension, abduction, adduction, circumduction, and rotation Motions possible are flexion and extension Ball-like structure fits into a cup-like depression Covex surfac fits into a concave surface

11.2.5 Describe the structure of striated muscle fibres, including the myofibrils with light and dark bands, mitochondria, the sarcoplasmic reticulum, nuclei and the sarcolemma.

Muscle 3 types Striated (skeletal) Cardiac Smooth (non-striated)

Striated (Skeletal Muscle)

Sarcomere

The Sarcomere

11.2.6 Draw and label a diagram to show the structure of a sarcomere including Z lines, actin filaments, myosin filaments with heads, and the resultant light and dark bands.

11.2.7 Explain how skeletal muscle contracts, including the release of a=calcium ions from the sarcoplasmic reticulum, the formation of cross-bridges, the sliding of actin and myosin filaments, and the use of ATP to break cross-bridges and re-set myosin heads.

11.2.8 Analyse electron micrographs to find the state of contraction of muscle fibres.

Electron micrograph showing contraction of one sarcomere