Periderm

Key concept

The periderm is a superficial layer of cells which develops from the primordial single-cell-layered epidermis and forms a transient covering for the epidermis during much of the remainder of its development. Periderm is a unique feature of developing epidermis; no similar structure occurs in the development of other epithelia.

Bullet Summary

• Week 5-6: Pavement epithelium
• Week 8: Microvilli
• Week 11: Central blebs form
• Week 16: Complex blebs form
• Week 17: Regression begins
• Week 24: Involution complete

Introduction

The periderm goes through distinct developmental phases and is ultimately sloughed into the amniotic fluid when differentiation of the underlying epidermal layers is complete. The function of the periderm is not known, but is thought to be related to transport/exchange between the fetus and the amniotic fluid.

To see how the periderm develops and to study the morphologic changes that suggest a transport/exchange function for this epithelium click on one of the buttons below:

Weeks 5-6
Week 8
Week 11
Week 16
Week 17
Week 24