Bio 322 Physio Ex 9 Skeletal Muscle Physiology

Do the skeletal muscle length affect muscle contraction?
Yes, there is an optimum length that will achieve maximum muscle tension

What are thin filaments on a sarcomere?

What are thick filaments on a sarcomere?

What happens when a sarcomere from a muscle is overstretched?
Miocene heads cannot grab on to the muscle and cannot exert a large contraction

What happens when a muscle is under stretched?
If over/under stretched muscle won’t have the maximum muscle contraction available

Does the length of the A band change during sarcomere shortening?
No, myocin filaments pull actin which don’t change the length

Does the length of the I band change during sarcomere shortening? Why or why not?
Yes due to the I band being pulled by the miocin filaments?

If the supply of ATP to a shortening muscle is completely depleted, what will happen to the cross bridge cycle?
ATP is required to dislodge the myosin heads from the actin filaments in the cross bridge cycle> if no ATP was available, it would cause you to remain in a contracted state

What is the name of the phenomenon that results from complete ATP depletion?
Rigor Mortis

What happens to muscle force if the muscle is stimulated by a voltage above the maximal stimulus? explain
All the muscle fibers are already recruited by the motor neurons and it would plateau out

A decrease in the maximal force produced by contracting skeletal muscles despite a continuous high frequency stimulus is called –>

What causes fatigue?
Accumulation of lactic acid, inorganic Phosphorous, and ADP, or an oxygen debt

What is the difference between a thigh muscle vs an eye muscle? (thigh muscle–> large, eye muscle–> small)
Thigh muscles have more muscle fibers contracting causing more motor unit recruitment

What is an isotonic movement?
Force> than the load, this would be a pushup or a squat

What is an isometric movement?
Load > the force, this would be a plank

When actin/myosin interactions are taking place, are you using ATP?

Do you think isotonic movements can become isometric muscle contractions? If so, when?
Yes, if you become fatigued. IF the force of contraction becomes less than the weight of the load weight, the movement becomes isometric

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