The two principal types of connective tissue in a
muscle are collagen and myofibrils. The entire muscle is wrapped in collagen to
form a fascicle. Looking at one muscle fiber, you will see that almost the
entire cross section of the muscle fiber is composed of long, cylindrical
strands of proteins called myofibrils<span>. </span>
Refraction is the change in direction of waves that occurs when waves travel from one medium to another. Refraction is always accompanied by a wavelength and speed change. Diffraction is the bending of waves around obstacles and openings.