|
| |
| Pigmentation |
Mainly
determined by melanin
|
| |
Melanin
producted by melanocytes
•
tyrosinase
•
tyrosine
•
‘melanization of melanosomes’
|
| |
Melanin
•
Provides defence against UV radiation
•
Racial differences which affect skin colour
|
| |
| Keratinisation |
| |
Epidermis
is ‘keratinizing epithelium
• Affected by mechanical stress
•
Keratin is form of protein
•
Desquamation
•
Cells change shape, cellular contents and structure as they move
through epidermis
|
| |
|
| BASAL
LAYER |
|
Single
layer - columnar epithelium
• Tonofilaments - tonofibrils
•
Desmosome/hemidesmosome
|
|
| |
|
PRICKLE
LAYER |
|
• tonofilaments
interlace
• contain keratinosomes
|
|
| |
|
GRANULAR
LAYER |
|
•
Flattened polyhedrons
•
large dense keratohyalin granules
|
|
| |
|
HORNY
LAYER |
|
•
Large flattened cells
•
Tightly packed fibrils
•
No nucleus or other organelles
|
|
| |
Keratinization
affect by:
•
Dermis
•
Vitamin A
•
Hydrocortisone
•
Epidermal chalones
|
| |
| Links: |
| Structure
and Function of the Stratum Corneum from the American Academy
of Dermatology |
| |
|
| |
