Early Epidermis

Key concept

The epidermis is derived primarily from ectoderm. Downward proliferations of epidermal cells differentiate to produce the epidermal appendages of hair, glands (apocrine, eccrine, and sebaceous) and nails. Cells from other germ layers do contribute to the final product.

Introduction

The earliest precursor of the epidermis, the ectoderm, is already in evidence in the implanted blastocyst by day 7-8 after fertilization. Over the next three to four weeks, the signature structure of primate epidermis, the periderm, is formed.

Periderm