We have microfilaments, we have intermediate filaments and also microtubules. And let's begin by discussing the microfilaments. The microfilaments are the thinnest of the three types of protein fibers and their diameter ranges from six to 7. They are basically composed entirely of one type of linear protein known as actin. And one common example of the use of microfilaments is in the contraction of cells and specifically in the contraction of muscle cells, one type of cell found in our bodies. So basically during muscle contraction what happens is there is an interaction taking place between the actin found in our microfilament as well as a different type of protein known as meiosin.