11.2.1 State the roles of bones, ligaments, muscles, tendonns and nerves in human movement.
Bones: provide framework; protects organs; store minerals
Ligaments: attaches bones to bones
Muscles: capable of contraction; attaches two bones across a joint
Tendons: attaches muscles to bones
Nerves: impulses sent from brain to muscles stimulates contraction of nerves
1. humerus (bone)
2. tricep (muscle)
3. joint capsule
5. tendon of tricep
7. synovial fluid
8. ulna (bone)
9. radius (bone)
10. tendon of bicep
11.2.3 Outline the functions of the structures in the human elbow joint named in 11.2.2.
Cartilage: covers bones at joints; smooth connective tissue; absorbs shock
Synovial fluid: lubricates the joint; found in joint capsule
Joint capsule: encloses synovial cavity; surrounds the joint
Radius and ulna: help rotate forearm
Biceps and triceps: help flex and extend at elbow joint
11.2.5 Describe the structure of striated muscle fibers, including the myofibrils with light and dark bands, mitochondria, the sarcoplasmic reticulum, nuclei and the sarcolema.
Striated muscle: skeletal muscle
Myofibrils: bundles of muscle filaments; make up a muscle fiber
Mitochondria: found betweem myofibrils
Sarcoplasmic reticulum: modified ER; wraps around myofibrils; stores calcium
Nuclei: multinucleated muscle fibers formed from fusing several cells
Sarcolema: muscle fiber membrane
11.2.7 Explain how the skeletal muscle contracts, including the release of calcium ions from the sarcoplasmic reticulum, the formation of cross-bridges, the sliding of the actin and myosin filaments, and the use of ATP to break cross-bridges and re-set myosin heads.
Impulse travels down the T-tubule to sarcoplasmic reticulum --> calcium is released
Calcium moves tropomyosin --> opens myosin binding sites and myosin head binds to aactin filaments creating cross-brides
ATP on myosin head is hydrolyzed into ADP and Pi which cocks the myosin head and causes the head to become agitated and lead to the sliding of actin and myosin filaments
ATP is hydrolized to cock the myosin heads
New ATP binds to myosin heads which breaks cross bridges
11.2.8 Analyze electron micrographs to find the state of contraction of muscle fibers.
Relaxed muscle fibers will have wide light bands, while contracted muscle fibers will have narrow or no light bands, because the filaments are over-lapping.
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