Human skin is the site of many complex structures and dynamic processes as demonstrated in Figure 1-1 and Table 1-1. These processes include barrier and immunologic functions, sensation, vitamin D synthesis, thermoregulation, and protection from ultraviolet (UV) light and trauma.
Cross-section of skin. Diagram showing layers of the skin, appendages, blood vessels, sensory nerve fibers, and sensory receptors.
Table 1-1.Structure and Function of the Skin ||Download (.pdf) Table 1-1. Structure and Function of the Skin
|Structure and Function
|Semipermeable barrier with "bricks" (stacked cornified cells) and "mortar" (ceramides, cholesterol, and fatty acids) like construction.
|Cells contains keratohyalin granules which are primarily composed of profilaggrin.
|Contains desmosomes for intercellular adhesion.
|Dendritic cell important in the modulation of the adaptive immune response.
|Specialized cell with neuroendocrine function.
|Dendritic cells that produce melanin for ultraviolet light protection.
|Basal cell layer
|Contains the stem cells that divide and produce the rest of the keratinocytes in the epidermis.
|Interface between the epidermis and dermis.
|Amorphous gel of mucopolysaccharides that is the substrate for the dermis.
|Network of fibrous proteins for skin tensile strength.
|Fibrous proteins responsible for skin elasticity.
|Cells that produce ground substance, collagen, and elastic fibers.
|Leukocytes that release histamine and heparin.
|Leukocytes which phagocytize and present antigen.
|Sweat glands which help in temperature regulation.
|Axillary and anogenital glands responsible for body odor.
|Component of pilosebaceous unit which produces sebum.
|Component of pilosebaceous unit that produces the hair fiber.
|Somatic sensory and sympathetic autonomic nerves
|Supply blood vessels, glands, and hair follicles.
|Specialized nerve receptor for light touch.
|Specialized nerve receptor for pressure and vibration.
|Two horizontal plexuses in the dermis which are connected and can shunt blood flow.
|Parallel to blood vessels with two plexuses for flow of plasma.
|Provides protection from cold and trauma. Essential for storage of energy and metabolism of sex hormones and glucocorticoids.
|Connective tissue layer overlying the muscle beneath the fat.
One of the most important function of human skin is to act as a barrier between us and the external environment.1 It protects against a variety of forms of physical damage, ranging from desiccation to infection, heat loss, and UV damage.2 The skin is a multilayered stalwart against these insults. First, the stratum corneum, with its corneocytes wrapped in cornified cell envelopes, water-impenetrable lipid lamellae, and filaggrin, forms a barrier that protects us from infectious organisms and water loss. Tight junctions help seal the spaces between neighboring cells in the stratum granulosum. Langerhans cells in the ...