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# HAIR REGION - **Medulla** - consists of central region, surrounded first by the cortex and then by a protected cuticle - **Cortex** - composed of several layers of flattened cell, bulky layer - **Cuticle** - it encloses cortex, formed by a single layer of cells - **Dermal sheath** - it enclosed in...

# HAIR REGION - **Medulla** - consists of central region, surrounded first by the cortex and then by a protected cuticle - **Cortex** - composed of several layers of flattened cell, bulky layer - **Cuticle** - it encloses cortex, formed by a single layer of cells - **Dermal sheath** - it enclosed inner epithelial sheath - **Arrector pili** - small bands of smooth muscle cells, connect each hair follicle to the dermis. # HAIR FACTS - Testosterone and good nutrition promote hair growth - Growth occurs in cycles: active and resting - Scalp hair grows for 3 years and rests for 1 year - Eyelashes grow for 30 days and rests for 105 days - We lose about 90 scalp hairs per day - Grey hair is the loss or fading of melanin - Male pattern baldness is from the loss of hair follicles # NAILS - Thin plate with layers of dead stratum corneum cells with hard keratin. # NAIL STRUCTURE - Scalelike modification of the epidermis that corresponds to the hoof or claw of other animals. - Nails are transparent and nearly colorless but they look pink because of the rich blood supply in the underlying dermis. 1. **Nail Body** - visual part, free edge 2. **Nail Root** - covered by skin 3. **Nail Folds** - border of the nail, overlapped folds of skin 4. **Nail Beds** - the stratum basale of the nail - Epidermis extends beneath the nail. 5. **Nail Matrix** - thickened proximal area; responsible for nail growth, produces nail cells - Heavily keratinized and die 6. **Cuticle** - stratum corneum that extends into nail body. 7. **Lunule (crescent)** - thickened nail matrix that appears as white crescent.