Ch 6 nail and hair anatomy Flashcards
What is nail matrix?
Actively growing part of nail at proximal end of nail body
What is lunula?
Whiteish area on proximal end of nail body
What are nail folds?
Folds of skin overlapping nail
What is eponychium (cuticle)?
Narrow band of epidermis from nail wall to nail body
What is hyponychium?
The free nail edge
What is free edge?
No underlying capillaries (whiteish)
What is nail body?
Underlying capillaries (pinkish)
What is nail plate?
The nail edge, root, and body
What is nail bed?
Layer of living epidermis covered by nail body
What is nail root?
Part embedded in skin
What is lanugo hair?
Fine, unpigmented, downy hair
Where don’t we generally find hair?
Sole and palms
What is vellus hair?
Fine hair, upper and lower limbs
What is terminal hair?
Coarser, pigmented longer: scalp, eyebrows, eyelashes
6 functions of hair
Protection, facial expression, heat, retention, sensory reception, visual identification, chemical signal dispersal
What produces hair color?
Synthesis of melanin in matrix
What causes gray hair?
Reduction in melanin
What causes white hair?
Stoppage of melanin
What are the three phases of hair growth?
Anagen, catagen, telogen
What is anagen phase?
Active phase
What is catagen phase?
Brief regression period
What is telogen phase?
Resting phase
What is hair matrix?
Structure at base, epithelial cells divide, and new cells produce
What is medulla?
Flexible, soft keratin
What is hair cuticle?
Single cell layer around cortex
What is cortex?
Flattened cells closer to outer surface
What is hair follicle?
Oblique tube surrounding hair root
What is CT root sheath?
Hair follicle originating in dermis
What is epithelial tissue root sheath?
Hair follicle originating from epidermis
What is arrector pili?
Thin ribbons of smooth muscle and causes goosebumps
