Hi there, I am a myosin fiber, I am ( a fibrous protein that forms (together with actin) the contractile filaments of muscle cells and is also involved in motion in other types of cells) a very important part of your body that allows you to contract and move your muscles! Over to the left you will see a picture of me. I have two heads (known as myosin heads) that will grab on to another important component in muscle contraction; actin. Go ahead and flip to the next page to see what I am talking about.

Over to the left, you will see an image of actin and I about to link up and slide which will cause the contraction of your muscle. To accomplish this, a block had to be first removed so I could get to the actin. This block was called tropomyosin. To remove that block, calcium had to be released which would in turn allow for me to grab onto the actin (a protein that forms (together with myosin) the contractile filaments of muscle cells, and is also involved in motion in other types of cells.)

To be able to contract the muscle, first you must have ATP, which is how energy is stored before it can be used. This allows for the z- disks (Z-discs are plate-like structures in sarcomeres to which the plus ends of actin filaments are localized, or they can be defined as the center of the I-band.) to shorten and contract the muscle from within the sarcomere making it shorter.