Dermis Layer

Dermis: The Skin's Functional Layer

The dermis lies beneath the epidermis and is composed of two layers: the papillary dermis and the reticular dermis. Unlike the epidermis, which consists of epithelial tissue, the dermis is primarily made of connective tissue.

Papillary Dermis

The papillary dermis is the topmost layer of the dermis. It is characterized by thin, loose connective tissue, allowing for movement and flexibility.

• Blood Vessels: The papillary dermis is the most superficial layer of skin containing blood vessels. Capillaries deliver oxygen and nutrients to both the dermis and the epidermis.

• Nerve Endings: Responsible for the perception of touch and pain, these nerve endings relay signals to cell bodies located further away.

Reticular Dermis

The reticular dermis sits below the papillary dermis. It contains thicker, denser connective tissue that anchors structures within the skin.

• Glands: Sweat glands and other exocrine glands originate in the reticular dermis, extending ducts to secrete contents onto the epidermis.

• Hair Follicles: Anchored within the reticular dermis, hair follicles allow hair to grow and protrude through the epidermis.

• Arrector Pili Muscle: This muscle is connected to the hair follicle and is responsible for making hair stand up when cold or scared.

脂肪 Hypodermis: The Insulating Layer

The hypodermis, also known as subcutaneous fat, is located below the dermis. It is primarily composed of fat and serves two main functions:

• Shock Absorption: Fat provides insulation, helping to withstand traumatic injuries.

• Insulation: Fat insulates underlying tissues, such as muscle and bone.

🩺 Clinical Significance: Diagnosing Burns

The depth of a burn determines its degree, corresponding to different layers of the skin.