Structure and Function of the Skin and Its Appendages

Overview of Skin Layers and Their Functions

The skin is the largest organ of the human body, serving as a crucial barrier against environmental hazards while regulating body temperature and sensation.

Skin Layers

Epidermis

The outermost layer, composed primarily of keratinocytes, provides waterproofing and defense against pathogens.

Dermis

The middle layer contains connective tissue, blood vessels, nerve endings, and appendages such as hair follicles and sweat glands.

Hypodermis

Also known as the subcutaneous tissue, this layer provides insulation and mechanical cushioning.

Functions of the Skin

• Protection: Shields against microbial invasion and physical damage.
• Temperature Regulation: Sweat glands and blood vessels assist in thermoregulation.
• Sensory Reception: Nerve endings detect pressure, pain, and temperature changes.
• Excretion: Sweat glands eliminate waste products.
• Synthesis of Vitamin D: Ultraviolet (UV) exposure triggers vitamin D production.