I 1.6

Question 1

• Plates of tightly packed, hard, dead, keratinized epidermal cells that form a clear, solid covering over the dorsal surfaces of the distal portions of the digits
• Parts: Nail body, Free edge, Nail root, Nail bed, Eponychium (cuticle), Nail matrix

Answer 1

Nails

Question 2

Nails
Part:
- Visible portion of of the nail
- Comparable to the stratum corneum of the epidermis, with the exception that its flattened, keratinized cells fill with a harder type of keratin and cells are not shed
- Below is a region of epithelium and a deeper layer of dermis

Answer 2

Nail body

Question 3

Nails
Part:
- Part of the nail body and may extend past the distal end of the digit
- White in color because there are no capillaries underneath.
- Underneath is the hyponychium: a thickened region of stratum corneum which secures the nail to the fingertip

Answer 3

Free edge

Question 4

Nails
Part: Free edge
- a thickened region of stratum corneum which secures the nail to the fingertip

Answer 4

hyponychium

Question 5

Nails
Part:
- Portion of the nail that is buried in a fold of skin
- A whitish, crescent-shape area of the proximal end of the nail body called the lunula can be seen

Answer 5

Nail root

Question 6

Nails
Part:
- The skin below the nail plate that extends from the lunula to the hyponychium
- Epidermis lacks a stratum granulosum

Answer 6

Nail bed

Question 7

Nails
Part:
- A narrow band of epidermis that extends from and adheres to the margin of the nail wall
- Occupies the proximal border of the nail and consists of stratum corneum

Answer 7

Eponychium (cuticle)

Question 8

Nails
Part:
- Portion of the epithelium proximal to the nail root
- Divides mitotically to produce new nail cells
- Growth rate is determined by the rate of mitosis in matrix cells, influenced by factors like person’s age, health and nutritional status
- Growth also varies according to the season, time of day, and environmental temperature

Answer 8

Nail matrix

Question 9

Nails: Additional Note

Answer 9

✓ The average growth in the length of fingernails is about 1mm (0.04 in) per week.
✓ Toenails grow slower compared to fingernails.
✓ The longer the digit, the faster the nail grows

Question 10

Nails: Function

Answer 10

✓ Protect the distal end of the digits
✓ Provide support and counter pressure to the palmar surface of the fingers to enhance touch perception and manipulation
✓ Allow us to grasp and manipulate small objects, and they can be used to scratch and groom the body in various ways