Ultraviolet Damage and Repair Flashcards Preview

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Flashcards in Ultraviolet Damage and Repair Deck (14):
1

Which type of UV light is responsible for most of the negative physiological effects?

UVB, although UVA can also cause DNA damage

2

UVA is ______ than UVB.

longer (it can thus penetrate deeper into the skin and affect fibroblasts and connective tissue)

3

Why don't we worry about UVC and solar light with shorter wavelengths than UVB?

Because the middle and upper atmosphere scatter it

4

_____ light induces vitamin D synthesis.

UVB

5

List the five main categories of UVR's effects on skin.

(1) vitamin D synthesis; (2) damage to DNA, RNA, proteins, and lipids; (3) apoptosis; (4) pro-inflammatory effects; and (5) induction of innate defenses

6

_____ is the most effective UV light at inducing ROS generation and immunosuppression.

UVA

7

UVB acts primarily on _________.

Langerhans cells, keratinocytes, and melanocytes

8

What is the precursor molecule in vitamin D synthesis?

7-dehydrocholesterol

9

Other than thymine dimerization, what does UVR do to DNA?

Pyrimidine 6,4 pyrimidone formation (UVB), and hydroxyguanosine formation (UVA and singlet oxygen)

10

By what two mechanisms does UVR induce immunosuppression?

(1) stimulating the immune-regulatory molecules, such as IL10; and (2) decrease in Langerhans proliferation

11

What pro-inflammatory molecules are released by UVR?

IL-1, TNF-alph, prostaglandins, leukotrienes, and histamine

12

List four ways that the skin can protect itself against UV damage.

DNA repair, apoptosis of excessively damaged cells, ROS defense, and melanin

13

Where are melanocytes located?

Stratum basalis

14

Thioredoxin reductase is an ________.

enzyme that protects against reactive oxygen species

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