Topic 11 cont’dMuscles and Movement

Roles of ________ in human movement• Bones – provide anchorage for muscles; act as levers to

change the size and direction of forces

• Ligaments – connective tissue; connect bone to bone; allow certain movements and prevent others (dislocations)

• Muscles – attach to bone and provide the force necessary to change the position of the bones and therefore the body

– Only work when contracting = antagonistic pairs

Cont’d

• Tendons – connective tissue that connects muscle to bone; transmit the forces generated by the contraction of muscle

• Nerves – innervate voluntary and involuntary muscles and are the cause of all muscle contraction

Elbow Joint

Label the human elbow joint

Structure and function• Bicep – flexes the joint• Tricep – extends the joint• Humerus – attachment point for the triceps and

biceps• Ulna – bone to which the triceps is attached• Radius – bone to which the bicep is attached• Cartilage – covers the bones, prevents friction• Synovial fluid – lubricates joint; prevents friction• Joint capsule – seals the joint; helps prevent

dislocation

Hip joint vs. Knee joint• Hip - ball and socket

joint

• Can flexion, extension, rotate, abduction and adduction

• Knee – hinge joint

• Flexion and extension

Structure of striated muscle fibers

Sliding Filament Theory of How Muscles Contract

Sliding Filament Theory Animation

• www.blackwellpublishing.com/matthews/myosin.html

• http://bcs.whfreeman.com/thelifewire/content/chp47/4702001.html

ELECTRON MICROGRAPHS of Sarcomeres relaxed and contracted