NEED ANSWERS OF ALL THE QUESTIONS RELATED TO FOLLOWING PROBLEM 2. During a perio

Question

NEED ANSWERS OF ALL THE QUESTIONS RELATED TO FOLLOWING PROBLEM

2. During a period of high-intensity exercise a myofiber reaches fatigue and its force output is minimal.

A. The max force output of the myofiber is 10% of normal. Assuming that we can freeze time at the moment the fatigued myofiber produces this max force, what would be the available concentration of Ca2+ in the sarcoplasm?

B. Assuming that the reduction in force is due to [Pi] above 20 mM interfering with the calcium transient, what concentration of calcium phosphate would you expect in the sarcoplasm during the max contraction of the fatigued myofiber?

C. Why might the calculation in B not be entirely accurate?

D. Why would additional action potentials not increase force output?

Explanation / Answer

The contraction of a skeletal muscle fiber is triggered by an action potential occurring in the sarcolemma (plasma membrane) of that muscle fiber

The action potential propagates down the sarcolemma and is conducted down transverse tubules into the interior of the cell. This, in turn triggers the release of Ca2+ from the sarcoplasmic reticulum

ified endoplasmic reticulum) into the cytosol. The Ca2+ binds to troponin on the thin filament and causes it to undergo a conformational change

This change in the shape of troponin shifts the position of tropomyosin on the thin filaments, exposing binding sites for myosin on the underlying actin and enabling crossbridge formation (the bonding of myosin on the thick filaments to actin on the thin filaments) to commence.

Related Questions

Navigate

• Browse (All)
• Browse N
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.