Flashcards in Pigmentary System Deck (7)
Where is melanin formed? What happens to it as cells mature?
- melanocytes produce melanosomes in basal layer of epidermis
- transferred to keratinocytes
- during anagen transerred to hair matrix cells
- as keratinocytes -> stratum coreum granules degraded by lysosomes.
2 types of melanin
- oval melonsomes
- much researched
- red bornw/yellow
- soluble in alkali
- round melanosomes
- little researched
Where must diseases affect in order to cuase pigmentary changes?
- hair matrix
- basal layer of epidermis
causes of hyperpigmentation?
- recent inflammation
- lentigo (macular melanosis in mature dogs, +- epidermal thickening)
- lentigo simplex (orange cats <1yr black spots on lips, gums, eyelids, nose)
Causes of hypopigmentation?
- damage to epidermis/hair follicle
- interface autoimmune disease
- viteligo (autoimmune attack against melanocytes)
2 causes of sunlight based skin damage?
1. excessive exposure on lightyl pigmented skin
2. photosensitivity or photoallergy (reaction of chemical promoted bu UV light)