Rete pegs

Rete pegs are extensions of the epidermis that project into the underlying dermis. These structures are also known as rete ridges. They play a crucial role in the structural integrity and function of the skin.

Structure

Rete pegs are formed by the downward projections of the epidermis into the dermis. They interdigitate with the upward projections of the dermis known as dermal papillae. This interlocking arrangement increases the surface area for the exchange of oxygen, nutrients, and waste products between the epidermis and dermis. It also helps to anchor the epidermis to the dermis, providing mechanical strength to the skin.

Function

The primary function of rete pegs is to enhance the adhesion between the epidermis and dermis. This is particularly important in areas of the skin that are subject to mechanical stress, such as the palms of the hands and the soles of the feet. By increasing the surface area of contact, rete pegs help to distribute mechanical forces more evenly across the skin, reducing the risk of skin tears and blisters.

Clinical Significance

Changes in the structure and function of rete pegs can be associated with various skin conditions. For example, in psoriasis, the rete pegs are often elongated and thickened, contributing to the characteristic appearance of the skin in this condition. In contrast, in conditions such as aging and atrophic dermatitis, the rete pegs may become flattened, leading to a loss of skin elasticity and an increased risk of skin injury.

Histology

Under the microscope, rete pegs can be observed as downward projections of the epidermis into the dermis. They are composed of the same layers as the rest of the epidermis, including the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. The interface between the rete pegs and the dermal papillae is often irregular, reflecting the complex interlocking arrangement of these structures.

See Also

• Epidermis
• Dermis
• Psoriasis
• Aging
• Atrophic dermatitis