Looking Deeper Into the skin Skin Proteins and Appendages
Skin Proteins Keratin – strengthens & waterproofs Collagen – strengthens, helps in wound repair, provides structural support Elastin – provides stretchiness
Skin Proteins Melanin – UV protection, skin color Freckles Sun spots Vitiligo Albinism
Skin Appendages - Glands Sebaceous glands Oil glands – secrete sebum Softens & moisturizes skin, inhibits bacteria Connected to hair follicles Acne is inflamed sebaceous glands
Skin Appendages - Glands Sudoriferous (sweat) glands: Apocrine Mainly in hairy places Stimulated by stress/excitement Possible pheromone source Is main source of body odor when digested by bacteria Eccrine Found everywhere Thermoregulation
Skin Appendages - Hair Made of highly keratinized dead epithelial cells Formed by follicle & nourished by dermal papilla Functions Arrector pili – attached muscles that cause goosebumps
Hair Structure Cuticle – protective outer layer Cortex – largest area, filled with melanin Medulla – center, can be hollow or filled with cells
Hair Growth Patterns Three main phases: Anagen – grows Catagen – slows, ends when it stops Telogen – rests, pushed out by new hair
Skin Appendages - Nails Tightly packed keratinized cells Grow from lower layer of epidermis No pigment - colorless