The integumentary system is the body’s outer covering. According to Cleveland Clinic, it is made up of the skin, hair, nails, and the glands in the skin, along with the nerves and blood vessels that support them. Together these parts form a physical barrier against bacteria, injury, and sunlight, help regulate body temperature, and let you sense touch, heat, and cold.
The skin itself has three layers: the epidermis (the outer, waterproof layer that gives skin its color), the dermis (the thickest layer, which holds sweat and oil glands and hair follicles), and the hypodermis (a fatty layer that insulates the body). The glands include sweat (sudoriferous) glands, oil-producing sebaceous glands, ceruminous glands in the ear that make earwax, and mammary glands. Hair is made of the protein keratin, and nails protect the tips of the fingers and toes.
Source: Cleveland Clinic: Integumentary System
Image: Integumentary system, by Scientific Animations (scientificanimations.com), CC BY-SA 4.0, via Wikimedia Commons.