Functions of cutaneous and mucosal membranes in the immune system?

Cutaneous immune system Specialized immune tissues and APCs located under the epithelia of the skin, Mucosal immune system Specialized immune tissues and APCs located under gastrointestinal tract and respiratory tracts Most of immune cells are diffusely scattered, there are structures like tonsils in the pharynx and Payer patches in the intestine. Important property of Cutaneous and Mucosal immune systems is selective response to pathogenic bacteria, but not the commensal bacteria present on the skin and in the intestine.