The embryonic development of the integumentary system explains the development of skin, glands, hair, and nails. Also associated with the development of the integumentary system proper are the development of teeth and, in females, portions of the mammary glands.

The integumentary system forms from the embryonic ectoderm, the outer most or superficial layer of the embryonic germinal layers from which all structures and organs of the body ultimately form. Ectodermal cells ultimately form the epidermis (the outmost layer of skin), sweat and sebaceous glands, and hair and nails. Ectodermal cell also form the mammary glands and teeth.

Ectodermal layers proliferate (divide and increase in number) and thicken throughout embryonic development. The cells differentiate into the stratum germinativum (stratum translates to "layer"), stratum granulosum, stratum lucidum, and stratium corneum layer of the skin. At an early point in the differentiation process, the cells...