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Edu Level: NCSE
Skin System
The integumentary system, or skin system, includes the skin, hair, nails, and exocrine glands. As the body's largest organ, the skin protects against chemicals, diseases, UV light, and physical harm. Hair and nails extend from the skin's surface, offering additional support and defense against environmental damage. Additionally, exocrine glands produce sweat, oil, and wax, contributing to temperature regulation, skin protection, and moisture maintenance.
Functions of the Skin System:
- Protection: The skin defends against dehydration, microorganisms, bacteria, and harmful UV rays.
- Absorption: The skin can absorb oxygen, nitrogen, medications, and ointments.
- Sensation: Skin receptors enable us to feel touch, pain, heat, and cold.
- Temperature Regulation: The skin helps maintain body temperature by promoting sweating and muscle contractions.
- Immunity: The skin collaborates with the immune system to fend off microorganisms.
- Movement and Growth: The skin's elasticity allows for body coverage and supports movement.
- Excretion: Sweat glands in the skin eliminate waste products.
- Vitamin Production: When exposed to UV light, the skin produces vitamin D, essential for bone growth and strength.
Components of the Skin System:
The skin has three layers: the dermis, epidermis, and subcutaneous layer. The dermis contains sweat glands, hair follicles, and connective tissues. The outermost layer, called the epidermis, varies in thickness and contains melanin, which determines skin tone. The subcutaneous layer consists of fatty tissues that help retain heat.
Hair, Nails, and Melanin:
- Hair: Hair, made of dead keratinocytes, protects against UV radiation and provides insulation. Hair is generated by stem cells in hair follicles, while melanocytes determine its color. The hair shaft has layers called the cuticle, cortex, and medulla.
- Nails: Nails, composed of hardened keratinocytes, strengthen and protect fingertips and toes during various activities.
- Melanin: Melanin determines the color of the skin, hair, and eyes. Higher levels of melanin in darker skin offer protection against sun damage. Melanocytes increase melanin production when exposed to sunlight.
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