Trans 5 Flashcards
Wavelength of visible light
400-760 nm
Wavelength of UV range
200-400nm
UV radiation that is termed germicidal radiation
UVC
UV radiation that is most biologically active
UVB
UV that is referred as the black light
UVA
Predominant melanin pigment in dark skinned individuals
Eumelanin
Predominant melanin pigment in those w freckles and red hair
Pheomelanin
Most obvious responses of the skin to UV radiation
Sunburn or tan
Sunburn
Onset?(hr)
Peak? (Hr)
Persists for _ (wk)
3-6
12-24
1
T/F only UVB can cause sunburn
F, both UVA and UVB can cause sunburn pero mas effective lang ung UVB for causing erythema
UV-B induced inflammation
Effects of PGE2, NO and cytokines?
Vasodilation —> red skin
UV-B induced inflammation
Effect of neuropeptides?
Itch and pain
Difference between immediate tanning and delayed tanning
Immediate - no photoprotection
Delayed - increased epidermal melanin, so may photoprotection
Why is UVA the major contributor to photodamage than UVB
UVA (320-400nm) kasi can penetrate deeper into the dermis
Photoaging na may degradation of collagen
Wrinkles
What skin types are most at risk for skin cancer
Type I and II
Active ingredients of physical sunscreen
Zinc oxide, titanium oxide
Active ingredients of chemical sunscreen
Oxybenzone, avobenzone, octsalate, octocrylene, homosalate, octinoxate
Active ingredients of sunscreen that absorb both UVA and UVB
Oxybenzone, tiatanium, zinc oxide
Major lipid classes in stratum corneum
Ceramide (50%), fatty acid (10%), cholesterol (25%)
2 deficiencies contributing to xerosis
Perturbation in the intercellular lipid bilayer, deficiency on NMF
3 types of Moisturizers
Occlusives
Humectant
Emolient
How many hair follicles are there in the human scalp
100000-150000 hair follicles
Duration of catagen on hair scalp
3 weeks
Number of hairs shed per day
50-100
