Structure of the dermis and subcutis

Created 2008.

Learning objectives

• Name specific structural components of the basement membrane zone, dermis and subcutis

Introduction

The basement membrane zone is the communication channel between epidermis and dermis. The dermis supports the epidermis, providing nutrients and protecting it.

The dermis supports the epidermis by providing it with nutrients and toughness. It is made up of fibres and ground substance, with nerves, blood vessels and cellular infiltrations. The papillary dermis is the upper portion beneath the epidermis, characterised by thin haphazardly arranged collagen fibres, thin elastic fibres and ground substance. The lower portion is the reticular dermis, composed of coarse elastic fibres and thick collagen bundles parallel to the skin surface.

The dermis is full of double rows of peg-like formations called papillae under the basement membrane zone. Each double row underlies an epidermal ridge.

The papillary dermis is the portion of the dermis just below the epidermis. The reticular dermis extends from the papillary dermis to the fat.

Below this is subcutaneous tissue, the shock absorbing, and insulating and energy storage layer.

Structural components of skin 

Haematoxylin and eosin stained 

Basement membrane zone

Dermis

Subcutaneous tissue (subcutis, hypodermis)

Activity

List collagen subtypes, their differences, location and function.