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APPENDAGES OF THE SKIN

APPENDAGES OF THE SKIN. Hair Nails Sweat Glands Sebaceous Glands. Hair . Over most of the surface area of the body Length, thickness, type and color vary Composed of root shaft, outer cuticle layer, cortex, and medulla. Composition of hair . Cuticle

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APPENDAGES OF THE SKIN

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  1. APPENDAGES OF THE SKIN • Hair • Nails • Sweat Glands • Sebaceous Glands

  2. Hair • Over most of the surface area of the body • Length, thickness, type and color vary • Composed of root shaft, outer cuticle layer, cortex, and medulla

  3. Composition of hair • Cuticle • Single layer of flat, scale-like, keratinized cells that overlap each other. • Cortex • Elongated, keratinized, nonliving cells. • Where hair pigment in located. • As age, pigment granules are replaced by air.

  4. Composition of hair • Root • Part of hair implanted in skin • Embedded in hair follicle. • Papilla • End, contains capillaries to nourish hair follicle cells.

  5. Composition of hair Shape of follicle determines curl of hair • Oval – wavy • Flat – curly • Round -straight • Shaft • Protects from skin surface

  6. Composition of hair • Alopecia • Baldness • Arrector pili muscle • When pili muscle contracts, causes skin to pucker up around hair. • Goosebumps

  7. Nails • Hard structures covering the dorsal surfaces of the last phalanges of the fingers and toes. • Slightly convex on upper surface, concave on lower surface • Formed in nail bed or matrix.

  8. Nails • Formation • Epidermal cells appear as elongated cells • Fuse together to form hard, keratinized plates • As long as nail bed is intact, nail will always be formed.

  9. Sweat glands • Perspiration is 99% water w/only a small amount of salt and organic wastes • AKA sudoriferous glands • All over skin, large numbers under arms, palms of hands, soles of feet, and forehead.

  10. Sweat glands • Are tubular, w/coiled base and a tube-like duct that extends to form a pore in skin. • Under control of nervous system, activated by heat, pain, fever, and nervousness. • Lose about 500mL/day.

  11. Sweat glands • Ceruminous or wax glands are modifications of sweat glands. • Found in ear canals and produce ear wax.

  12. Sebaceous glands • Protects skin by a thick, oily substance known as sebum secreted by the sebaceous glands. • Sebum lubricates the skin, keeping it soft and pliable.

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