Muscles & Movement II
Muscle metabolism
Can classify by rate at which myosin hydrolyzes ATP
- Fast
- Slow
Can classify by kind of metabolism that produce ATP
- Oxidative
o Rely on oxidative phosphorylation to produce ATP
o Need steady supply of O2
o Lots of mitochondria
o Abundant blood supply
o Contain oxygen binding molecule myoglobin
- Glycolytic
o Use glycolysis
o Don’t need as much O2
Three types of muscle fibers
- Slow-oxidative
o Myosin hydrolyzes ATP slowly
o Do oxidative metabolism
§ Rich blood supply
§ Lots of mitochondria (why?)
§ Appear red or dark
§ For prolonged activity
· Marathoning, swimming long distances
- Fast-oxidative
o Myosin hydrolyzes ATP fast
o Do oxidative metabolism
§ Rich blood supply
§ Lots of mitochondria
§ Appear red or dark
§ For prolonged quick explosive actions
- Fast-glycolytic
o Myosin hydrolyzes ATP fast
o Do glycolytic metabolism
§ Not rich blood supply
§ Not a lot of mitochondria
§ For rapid, intense, short bursts of activity, like weightlifting
§ Fatigue rapidly
Different muscles have different amounts of these fibers interspersed with one another
How does an organism move?
- must attach muscle to two things, so can pull
- bone or exoskeleton
o tendons attach muscles to bones
- at a joint, two bones come together.
o ligaments connect bones together
- muscles can only exert force when they contract, so to move a joint must have antagonistic pairs of muscles
o When want more force of contraction, depolarize more fibers of a muscle
- muscle that bends a joint is flexor, muscle that straightens is extensor
- origin is the bone that does not move, insertion is the bone that does move
o biceps
§ connects to scapula and radius
· when curling weight, origin is scapula, insertion is radius
· when doing pull-ups, origins in radius, insertion is scapula
o The latissimus dorsi ( connect lower half of spine to upper humerus)
§ When it brings arm back (as on backstroke of crawl when swimming) the humerus is the insertion, whereas when you climb a rope, the spine is the insertion.
Problems
- Rickets
o Not enough calcium in bones, weak bones
§ Usually from not enough vitamin D
- Osteoporosis
o Too little bone because of
§ Age
§ Hormones
§ Lack of weight bearing exercise
o Osteoclasts break down (resorb) bone
o Can reverse by exercise, hormones
§ Makes osteoblasts outnumber osteoclasts
- Myasthenia gravis
o Destruction of acetylcholine receptors by immune system
o No one knows the trigger
- Multiple sclerosis
o Destruction of myelin by immune system
o Leads to action potential conduction problems
o No cure
- Muscular dystrophy
o Genetic disease
o Cannot produce normal dystrophin protein, due to gene deletion
o Causes problems in membranes of muscles, cells degenerate and muscles degenerate
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