Week 10 - Muscle Contraction: Explain 2

 Week 10 - Muscle Contraction: Explain 2

So far, we know that muscle stimulation is activated by a series of electrical nerve impulses sent from the brain to our muscles. As an action potential arrives at the neuromuscular junction within a muscle cell, acetylcholine (ACh) is released and causes actin and myosin to change shape. The interactions between ACh, calcium, actin, and myosin is what causes muscles to mechanically contract. This is referred to as excitation-contraction coupling. But how does calcium specifically aid in this process though? Please review the diagram below and see if you can connect the dots from last week to this week.

There is a lot going on at the cellular and molecular level for muscles to contract! Please re-review the excitation-contraction couplingLinks to an external site., specifically the section related to Figure 10.8 (left image below), of your textbook that you learned last week. Relate your understanding of the excitation process of muscle contraction you studied last week to the next step in the contraction process between actin and myosin within sarcomeres (image to the right below).

To further strengthen your understanding, please review these two videos: 

Sliding Filament TheoryLinks to an external site.

Cross-bridge cycleLinks to an external site.