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Flashcards in UV Light Lecture Deck (22)
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1

UVC Spectrum

200-290 Most potent but does not penetrate the atmosphere. When made it will kill epidermal cells

2

UVB Spectrum

290-320 The SUNBURN spectrum- SPF is based on this wavelength

3

UVA Spectrum

320-400nm Least potent but penetrates the deepest. Associated with SKIN CANCER and photo-aging

4

What increases UV exposure ?

Closer to the equator, Higher altitude, Higher reflective index ( Water-7%, Sand-25%, Snow-80%)

5

What affect do clouds have on UV ?

They scatter but do not absorb

6

What is the action spectrum of UV light ?

Different spectrums of light cause different diseases. The wavelength of the certain reaction is the action spectrum

7

What property of the UV light damages the skin ?

The chromophore of the light

8

What are the major UVB Chromophores ?

DNA, Urocanic Acid, Aromatic Amino Acids

9

What is the optimal wavelength for psorias treatment and Burning

295nm

10

What determines susceptibility to burning ?

Skin Phototype

11

What causes the symptoms of sunburn ?

Due to UVB
-Erythemia from vasodilation
-Heat from Inc. Blood flow
-Swelling from vaso-permibility
-Pain from cytokines

12

What are sunburn cells ?

They are cells damaged by UVB, they show inflammation, edema (Intracell and perivascular) perkeritosis and acanthosis

13

What casuses the immediate tanning response

UVA- Begins with radiation and fades within an hour. Does not protect against UVB.
**Oxidation and redistribution of melanin

14

What causes the delayed tanning response ?

UVB- visible after 72 hours and lasts for weeks. Caused by increased melanin synthesis.

15

What are solar elastoses ?

Clumps of melanin

16

What are some effects of chronic sun exposure ?

Telangiectasia, Pigment abnormalities, Solar elastoses, Solar letigines Cyst and comedone formation

17

What are the malignant changes in DNA from the sun ?

Cyclobutane dimers and 6,4 photoproducts

18

How does the body protect from these mutations ?

Stratum corneum- reflection
Melanin- absorption
Tumor Supressor genes
DNA repair pathways
Apoptosis

19

What causes Xeroderma Pigmentosum

A defect in nucleotide excision repair

20

What are the immune effects of sun exposure ?

Lymphocytes and Langerhans cells are damaged

21

Tanning beds ---->

Emit UVA... This is the cancer spectrum. Does not protect against UVB which is what gives you a sunburn.

22

How intense are tanning beds ?

They emit > 5x the amount of UVA than a unit of time in the sunlight.