Pigmentary System Flashcards
1
Q
Where is melanin formed? What happens to it as cells mature?
A
- 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
Q
2 types of melanin
A
> eumelanins - black - insoluble - oval melonsomes - much researched > phaemelanins - red bornw/yellow - soluble in alkali - round melanosomes - little researched
3
Q
Where must diseases affect in order to cuase pigmentary changes?
A
- hair matrix
- basal layer of epidermis
4
Q
causes of hyperpigmentation?
A
- recent inflammation
- endocrine
- lentigo (macular melanosis in mature dogs, +- epidermal thickening)
- lentigo simplex (orange cats <1yr black spots on lips, gums, eyelids, nose)
5
Q
Causes of hypopigmentation?
A
- damage to epidermis/hair follicle
- interface autoimmune disease
- viteligo (autoimmune attack against melanocytes)
6
Q
2 causes of sunlight based skin damage?
A
- excessive exposure on lightyl pigmented skin
2. photosensitivity or photoallergy (reaction of chemical promoted bu UV light)
7
Q
causes of photosensitisation>
A
- administered drugs
- absorbed from food (plants)
- abnormal metabolism due to hepativ disease/genetic abnormalities