Effect of Environment on Skin Flashcards Preview

Sem 3: Integ > Effect of Environment on Skin > Flashcards

Flashcards in Effect of Environment on Skin Deck (16):
1

Extensive epidermal and dermal damage, e.g. from severe burns or drug reaction, can cause death by what mechanisms?

  • Dehydration and shock
  • Infection
  • Heat loss and hypothermia
  • Others: protein loss, electrolyte imbalance, high-output cardiac failure, renal failure

2

What is hyperkeratosis and when does it occur?

Thickening of stratum corneum with rubbing or pressure, e.g. in guitarist fingers, feet - occurs slightly after UV exposure

3

How and why does tanning occur?

  • Melanocytes increase activity - make and transmit more melanin to basal keratinocytes
  • In response to UV exposure
  • Also some additional protection by skin thickening in response to UV 

4

Explain the cellular mechanism underlying the tanning response of melanocytes. 

  • DNA damage by UV rays increases levels of MSH (melanocyte-stimulating hormone)
  • MSH acts on MC1Rs (melanocortin-1 receptor) in melanocytes to stimulate increased melanin production and increased cell division

5

What is lichenification? 

More extreme form of hyperkeratinosis - reaction to excessive rubbing or scratching 

6

The ozone layer mainly blocks which UV wavelengths?

Mainly UVC, UVB and UVA to lesser extent

7

What form of UV light is the longest wavelength?

UVA

8

What is sunburn?

  • Radiation burn
  • Blisters, inflammation and cell death
  • Severe DNA damage
  • "Ever sunburnt" - increased risk of skin cancer

9

What are naevi? 

  • Moles - benign proliferations of melanocytes
  • Many or large naevi - risk factor for melanoma 

10

Describe the different types of skin cancer. 

  • Melanoma - melanocytes
  • Squamous cell carcinoma, basal cell carcinoma - keratinocytes

11

What are irritant contact dermititis and allergic contact dermititis? 

  • Irritant contact dermititis - common
  • Allergic contact dermititis - relatively uncommon - e.g. nickel:
    • Sensitisation - Langerhans cells process antigen and present to lymphocytes
    • Delayed hypersensitivity occurs at next exposure - memory T-cells

12

What is paronychia?

  • Nail fold infection
  • May be fungal or bacterial

13

What is tinea capitis?

Scalp ringworm - fungal 

14

What is impetigo?

Type of bacterial infection

15

Cellulitis is usually caused by what bacterium?

Streptococcus

16

Warts are caused by what virus?

Human papilloma virus (HPV)