Question: Fingernails and toenails are clear, hard derivatives of the stratum corneum. They are composed of very thin, dead, scaly cells, densely packed together and filled with parallel fibers of hard keratin.

Answer: Nail

Question: nail plate, which includes the free edge overhanging the tip of the finger or toe;

Answer: nail plate

Question: includes the free edge overhanging the tip of the finger or toe;

Answer: nail body

Question: extends proximally under the overlying skin

Answer: nail root

Question: folds of normal skin that surrounds the nail plate

Answer: nail fold

Question: separates nail fold from nail plate

Answer: nail groove

Question: The skin underlying the nail plate.-Its epidermis is called the hyponychium At the proximal end of the nail, the stratum basale thickens into a growth zone called the nail matrix.

Answer: nail bed

Question: Mitosis in the matrix accounts for the growth of the nail—about 1 mm per week in the fingernails and slightly slower in the toenails.

Answer: nail matrix

Question: an opaque white crescent at proximal end of nail

Answer: lunule

Question: A narrow zone of dead skin commonly overhangs this end of the nail.

Answer: cuticle (eponychium)

Question: can be valuable in medical diagnosis. -The fingertips become swollen or clubbed in response to long-term hypoxemia—a deficiency of oxygen in the blood stemming from conditions such as congenital heart defects and emphysema. -Dietary deficiencies may be reflected in the appearance of the nails. -An iron deficiency, for example, may cause them to become flat or concave (spoonlike) rather than convex.

Answer: The appearance of the fingertips and nails