The skin consists of three primary layers: the epidermis, the dermis, and the hypodermis. Each layer has distinct structural and functional characteristics.
1. Epidermis: This is the outermost layer of the skin. It is primarily composed of keratinocytes, which produce keratin, a protein that provides strength and waterproofing. The epidermis itself has several sub-layers, including the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale.
2. Dermis: Located beneath the epidermis, the dermis is composed of connective tissue, collagen fibers, elastin, and various cell types including fibroblasts, macrophages, and mast cells. The dermis also contains blood vessels, lymphatic vessels, nerves, and skin appendages such as hair follicles and sweat glands.
3. Hypodermis: Also known as the subcutaneous layer, the hypodermis is composed of loose connective tissue and fat cells. It provides insulation, cushioning, and energy storage.
