Skeletons & Muscles

1. Skeletons & Muscles

2. Animal Movement What are the advantages of being mobile? sessile mobile

3. Lots of ways to get around…

4. Lots of ways to get around… mollusk mammal bird reptile

5. Lots of ways to get around… bird insect mammal bird

6. Muscle involuntary,contract on their own voluntary involuntary evolved first

7. Organization of Skeletal muscle skeletal muscle tendon muscle fiber (cell) bundles of protein fibers protein fibers

8. Human endoskeleton ball & socket hinge 206 bones pivot

9. Muscles movement • Muscles do work by contracting • skeletal muscles come in antagonistic pairs • flexor vs. extensor • contracting = shortening • move skeletal parts • tendons • connect bone to muscle • ligaments • connect bone to bone

11. The Trigger: motor nerves • Motor nerves trigger muscle contraction

12. Fast twitch & slow twitch muscles • Slow twitch muscle fibers • contract slowly, but keep going for a long time • more mitochondria for aerobic respiration • long distance runner • “dark” meat = more blood vessels • Fast twitch muscle fibers • contract quickly, but get tired rapidly • sprinter • “white” meat

13. Muscle limits • Muscle fatigue • lack of sugar • lack of ATP • low O2 • lactic acid lowers pH which interferes with protein function • nerve fatigue • loss of chemical transmitter • Muscle cramps • build up of lactic acid • lack of energy (ATP) • ion imbalance • massage or stretching increases circulation

14. Diseases of Muscle tissue • ALS • amyotrophic lateral sclerosis • Lou Gehrig’s disease • motor neurons degenerate • Myasthenia gravis • auto-immune • antibodies to nerve transmitter chemical Stephen Hawking

15. Botox • Bacteria Clostridiumbotulinum toxin • blocks release of nerve transmitter • but botulism can be fatal! muscle