The first image below is an SEM image of a human hair as seen at approximately 1500 times magnification. A average human hair is approximately 100 microns in diameter and is a favorite yard stick for scientists, myself included, when describing very small objects. The hair in this particular image is slightly more than 70 microns in diameter. For comparison sake the diameter of this hair is roughly 1/3 the length of the side of a grain of salt as shown in our post on salt and pepper.
The second image below is of the same human hair now magnified 7000 times. At this magnification you can now clearly see the outer layer of hair called the cuticle. The cuticle is composed of dead cells, overlapping in layers, which form scales and give the hair shaft strength. Measurements of the image below show that the scales stick up from the main body of the hair shaft about 1 micron high.