1. Topic 11.2
Movement

2. Understanding: Bones & exoskeletons provide anchorage for muscles & act as levers
Exoskeleton = external skeleton that surrounds & protects crustaceans & insects
Levers change the size & direction of forces
Muscles are attached to insides of exoskeletons
Muscles are attached to outside of bones

3. Exoskeletons

4. Levers in the human body

5. Understanding: Movement of the body requires muscles to work in antagonistic pairs.
Antagonistic = opposite movements
When one contracts, the other relaxes
Why?
Because muscles can only pull, they don’t push
Example?
biceps brachii – flexes forearm
Triceps brachii – extends forearm

6. Application: Antagonistic pairs of muscles in an insect leg.

7. Skill: Annotation of a diagram of the human elbow
Joint = point where bones meet
Articulation = a movable joint
Most articulated joints have cartilage, synovial fluid & joint capsule
Cartilage
Structure = tough, smooth tissue covering ends of bone
Function = reduces friction between bones & absorbs shocks
Synovial fluid
Structure = fluid that fills cavity in joint between cartilages
Function = lubricates joint; prevents friction
Joint capsule
Structure =tough, ligamentous covering of joint
Function = prevents dislocation

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

9. Understanding: Synovial joints allow certain movements but not others
Similarities
Differences
Both are synovial joints
Both are involved in the movement of the leg

11. Understanding: Skeletal muscle fibres are multinucleate and contain specialized endoplasmic reticulum.

14. Fascicle vs Fiber

15. Understandings: Muscle fibres contain many myofibrils
Understandings: Muscle fibres contain many myofibrils. Each myofibril is made up of contractile sarcomeres.

16. Skill: Draw a labelled diagram of the structure of a sarcomere.

17. Understanding: The contraction of the skeletal muscle is achieved by the sliding of actin and myosin filaments.
Animation:

18. Skill: Analysis of electron micrographs to find the state of contraction of muscle fibres. Which one is contracted?

19. Understanding: Calcium ions and the proteins tropomyosin and troponin control muscle contractions
Animation:

20. Understanding: ATP hydrolysis and cross-bridge formation are necessary for the filaments to slide

22. Nature of Science: Fluorescence has been used to study the cyclic interactions in muscle contraction
Fluorescence = absorbing light of shorter wavelength (Xray, UV) and then emitting light of longer wavelength (visible light)
Researchers injected aequorin protein into acorn barnacle giant muscle fiber
Researchers attached fluorescent dye to myosin to show it “walking along” actin
Demonstrated the dependency of ATP on myosin detachment from actin