Nail apparatus and function

Question 1

What is the Nail Matrix important for?

Answer 1

• responsible for formation of nail plate, by producing onychocytes

Question 2

What are characteristics of the Nail Plate?

Answer 2

• Onychocytes form the flat, square transparent nail plate
• Connective tissue fibres hold it to the nail bed
• Curvature of the nail relates to the shapre of the underlying distal phalanx
• Has three layers

Question 3

what are the three layers of the nail plate?

Answer 3

• Dorsal (upper) - only a few cell layers thick, but consists of hard keratin
• Imtermediate (middle) - thickest cell layer, consists of softer keratin
• Ventral (lower) - think cell layer,

Question 4

What is the Lunula?

Answer 4

• the visible portion of the nail matrix
• crescent shapred/whitish area of the nail plate
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Question 5

What is the function of the lateral nail folds?

Answer 5

• to provide cushioning to the cutaneous lateral margins of the nail
• Contributes to the adherence of the nail plate to the nail bed
• More prominent in toes than fingers

Question 6

What are the characteristics function of the proximal nail fold?

Answer 6

• Fold of skin lying above the nail matrix
• covers about 1/4 of the nail plate
• responsible for protecting part of the nail matrix

Question 7

What is the cuticle known as, and what are its characteristics?

Answer 7

• Eponychium
• Extends from the proximal nail fold and adheres to the dorsal part of the nail plate
• Composed of keratinocytes
• has a protective role, stops pathogens entering at base of the nail plate

Question 8

What is the nail bed and its functions?

Answer 8

• Extends from the distal margin of the lunula to the hyponychium
• Consists of epidermis and dermis
• longitudinal ridges increase surface area to increase passage of nutrients to the nail, e.g. keratin
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Question 9

What is the hyponychium?

Answer 9

• skin beneath the tip of the nail
• forms a seal that protects the nail bed

Question 10

what is the onychodermal band?

Answer 10

• the seal between the nail plate and the hyponychium
• grey-ish line