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## Skin Protection ### A. Protection against Infection - Skin contains: - Langerhans cells in epidermis - Macrophages cells in dermis - These cells ingest foreign bodies and pathogens. ### B. Protection against Ultraviolet Light - Melanocytes are melanin-producing cells found in the basal...

## Skin Protection ### A. Protection against Infection - Skin contains: - Langerhans cells in epidermis - Macrophages cells in dermis - These cells ingest foreign bodies and pathogens. ### B. Protection against Ultraviolet Light - Melanocytes are melanin-producing cells found in the basal layer of epidermis. - Melanin particles are pigment molecules produced by melanocytes. - The molecular structure of melanin protects against molecular damage from overexposure to UV radiation and gives the skin a smooth, dark, tan appearance. ### C. Protection against Water Loss - The skin provides a protective barrier from the external environment and prevents dehydration (water loss). ## 2- Sensation - The skin contains an extensive network of nerve cells that detect and relay changes in the environment. - There are separate receptors for heat, cold, pressure, touch, and pain. - Damage to these nerve cells is known as neuropathy, which results in a loss of sensation in the affected areas. - Sense organs in the skin include: - Free nerve endings (pain and temperature change) - Meissner's corpuscle (touch) - Merkel disks (touch) - Ruffini's ending (pressure) - Pacinian corpuscle (pressure) - Thermoreceptor (senses heat) - Nociceptor (senses pain) - Meissner's corpuscle (senses touch) - Pacinian corpuscle (senses pressure)