Question

1. How does depolarization affect Ca²⁺ concentration released within a muscle cell and how does this affect contraction strength?

2. Why can a runner who is sprinting a 55-meter sprint hold her breath during the whole race?​

3. What is the cause of soreness after a heavy strength training session at the gym?​

Answer 1

1) Depolarization produced within the muscle fiber spreads along the sarcolemma of the muscle fibers to the T-tubule

This creates action potential which stimulates the sarcoplasmic reticulum of the muscle and helps in release of the calcium ions

This released calcium then activates the muscle fiber and causes the contraction of the muscle fiber

------>

i) Release of calcium causes binding to troponin molecules

ii) Binding to troponin causes exposure of actin binding site on troponin

iii) Myosin then binds to the actin binding site on troponin and cause cross bridge

iv) It results in muscle contraction