The Dermis, Hypodermis, and Essential Skin Functions

Dermis

The dermis is the part of the skin located below the epidermis, separated by the dermoepidermal junction. It is the connective tissue that holds the epidermis and contains the skin's nerves and sensory receptors. It is formed by a complex network of fibers embedded in a fundamental substance with few of its own cellular elements.

Function

• Provides resistance and flexibility to the skin.
• Acts as a protective barrier against internal agents, thus preventing infections.
• Serves as a reservoir for liquids.
• Stimulates the production of keratinocytes through keratogenesis.
• Participates in wound healing.

Structure

Papillary Dermis

This layer has a greater proportion of reticular fibers that participate in the dermoepidermal junction. Its function is to provide nutrients to the epidermis. For this, it has abundant lymphatic and blood capillaries. It is also responsible for sensation, as it possesses numerous nerve endings. It is richer in cells than in fibers.

Reticular Dermis

This is the deeper and larger compartment. Its function is to provide resistance to the skin, acting as a support for vessels, nerves, and appendages. It is composed of thick fibers and few fibrocytes.

Hypodermis

Also known as subcutaneous tissue, it is a fatty layer located under the reticular dermis. It is formed by a lattice of fatty lobes limited by fibers, which are further divided into lobules filled with adipocytes (fat cells).

Function

• Protective: Cushions against blows and trauma.
• Metabolic: The adipose tissue constitutes an energy reservoir.
• Plastic: Shapes the body according to age, sex, and nutritional status.
• Thermoregulation: The fat acts as thermal insulation.

Functions of the Skin

• Acts as a protective barrier and an energy reserve.
• Secretions like sweat and sebum are observed on its surface.
• It undergoes flaking and is colonized by saprophytic microorganisms (resident flora).
• Its primary function is to connect the individual with and adapt to the environment.
• It serves as an organ of communication and relationship, reflecting our vital actions.

Properties of the Skin

Distensibility and Elasticity

When the skin receives a blow, it stretches. If a certain limit is exceeded, it does not resist and breaks. Elasticity is the property of returning to its original position when the force ceases. When this property is disrupted, a rupture of fibers (stretch marks) can occur.

Resistance

This refers to the protection that the cells of the stratum corneum exert against trauma.