Skin Histology

1
Chapter 5

• Skin Histology
• Epidermal Derivatives
• J.F. Thompson, Ph.D.

2
Hair Distribution Varies Over the Body Surface
3
Hair Follicles
4
Hair Anatomy

• Shaft
• medulla - inner layer
• cortex - middle layer, pigments, air spaces
• cuticle - outermost layer, hard keratin
• Root
• similar to shaft, but within dermis
• Follicle - surrounds root
• Sheath - supports shaft root
• Bulb - enlarged layered structure at base where
  hair is generated
• papilla - areolar connective tissue, blood
  vessels supply nutrients
• matrix - germination layer of papilla (stratum
  basale) builds hair shaft
• Sebaceous glands release oil
• Arrector Pili smooth muscle

5
Hairs Lice
egg
crab louse
head louse
6
Arrector Pili (smooth muscle)
7
Sweat Glands
8
Sebaceous Glands
9
Nails

• tightly packed, hard, keratinized cells
• nail matrix - under root of nail
• site of nail growth
• transforms normal skin cells into nail cells
  which push forward
• 1mm/week in fingers slower in toes
• the longer the finger the greater the growth rate

10
Nails

• Tightly packed cells with hard keratin
• Nail matrix - under root of nail
• site of nail growth
• transforms normal skin cells into nail cells
  which push forward
• 1mm/week in fingers slower in toes
• the longer the finger the greater the growth rate

11
Hypodermis
12
End Ch 5

• Skin Histology
• Epidermal Derivatives