Peggy McLemore Nail Structure & Growth Chapter 21 Peggy McLemore Nail Structure & Growth

The Nail Nail Technical term - onyx Appendage of the skin Horny, translucent layer Protective plate that protects the tips of fingers & toes Part of the Integumentary system The skin and its accessory organs, such as the oil and sweat glands, sensory receptors, hair & nails Technical term - onyx

Composition Keratin Nail plate Healthy nail protein that forms base of all horny tissue Nail plate contains no nerves or blood vessels Healthy nail whitish & translucent in appearance w/ pinkish color of nail bed showing through

Composition Nail porosity water can pass through more easily than normal skin. water content of nail is related to the humidity of the environment 10% to 30% water content

Composition Nail porosity affects flexibility, less water content, more brittle the nail ointment-based conditioner reduces loss of water in the nail

Nail Anatomy Six basic parts – figure 21-2,pg. 739 Nail bed Matrix bed ( nail root ) Nail plate ( nail body ) Cuticular system cuticle, eponychium, hyponychium Nail folds nail anatomy is the same in fingernails & toenails

Nail Bed Skin where nail body rests Extends from lunula to just before free edge Attached to nail plate by a thin layer of tissue called the bed epithelium forces the plate to grow toward the end of the digit instead of growing straight up off the matrix bed Supplied w/ many nerves

Matrix Bed Where nail is formed Composed of matrix cells that produce the nail plate Contains nerves, lymph, blood vessels to nourish nails

Matrix Bed Extends from under nail fold at base of nail plate it can be seen as a whitish half-moon shape called lunula - half moon light color is caused by reflection of light where the matrix & connective tissue of the nail bed join Growth affected by poor health, nail disorders or injury to nail matrix

Nail Plate Horny nail plate or nail body Rests on & attached to nail bed Formed by matrix cells Constructed in layers layers are visible when nail splits Free edge extends over tip of finger or toe It takes 6 months for a nail to grow from the root to the free edge. Toenails grow about 1 mm per month and take 12-18 months to be completely replaced.

Cuticular System Crescent of toughened skin around base of nails If normal loose & flexible Seals area against foreign material & microorganisms Helps prevent injury & infection

Cuticular System Eponychium Hyponychium Extension of the cuticle at the base of nail a body that partly overlaps lunula Hyponychium The thickened corneum of the epidermis that lies beneath the free edge Seals the free edge of the nail to the normal skin, preventing external moisture, bacteria or fungi getting under nail

Specialized ligaments Ligament is a tough band of fibrous tissue that connects bones or holds an organ in place attach the nail bed & matrix bed to underlying bone located at the base of matrix & around edges of nail bed

Nail Folds Folds of normal skin surrounding nail plate Form the nail grooves or slits or furrows of the sides of the nail nail moves through the furrows as it grows The mantle is the deep fold of skin in which the matrix bed ( nail root ) is lodged

Summary Nail is an appendage of the skin Technical term onyx Six parts nail bed matrix bed ( nail root ) nail plate ( nail plate ) cuticular system specialized ligaments nail folds

Questions Describe a normal healthy nail? normal, healthy nail is firm & flexible, shiny, & pink in color. Its surface is smooth & unspotted, w/ no hollows or wavy ridges What is the technical term for nail? ONYX What is the nail composed of? mainly keratin, the same protein found in skin & hair

Questions Name the six basic parts of the nail? nail bed, matrix bed, nail plate, cuticular system, specialized ligaments, & nail folds What part of the nail contains the nerve & blood supply? matrix bed contains nerves, lymph, & blood vessels to nourish the nail

Questions Explain how the nail grows. normal nail grows forward, starting at the matrix & extending over the tip of the finger