[header] How to study the structure and function of human skin [title] Learn about the histology of skin in humans. [step] The skin of humans is composed of several histologic layers that are different than other creatures in the animal kingdom. This histologic structure is important for various reasons. 
One of them is its use as a selective physical barrier against foreign pathogens and harmful chemicals. At this level it serves as part of the nonspecific immune system in humans.