Effect of Environment on Skin Flashcards

1
Q

What is toxic epidermal necrolysis?

A

→ Detachment of the epidermis that is fatal

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2
Q

What are environmental insults?

A
→ UV light 
→ Physical trauma 
→ Microbes
→ Allergens
→ irritants
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3
Q

What are fast adaptations of the skin?

A

→ Sweating and vasodilation in the heat

→ Vasoconstriction in the cold

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4
Q

What are two slow adaptations of the skin?

A

→ Hyperkeratosis : thickening of the stratum corneum with rubbing or pressure
→ Melanocytes : tanning

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5
Q

What are AV shunts?

A

→ Anastomoses between arterioles and venules

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6
Q

What do AV shunts respond to?

A

→ thermoreceptors in the skin

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7
Q

What do AV shunts do?

A

→ Open and close to increase or decrease blood flow to the superficial vascular plexus in the papillary dermis

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8
Q

What can AV shunts in the face do?

A

→ Respond to emotion

→ blushing

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9
Q

What happens if AV shunts are shut off for too long?

A

→ danger of damage (frostbite)

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10
Q

What is the color of human skin due to?

A

→ Melanin and haemoglobin

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11
Q

What does melanin do?

A

→ protect against DNA damage and skin cancer

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12
Q

Where do melanosomes get transferred to?

A

→ basal keratinocytes

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13
Q

What happens to melanocytes during tanning?

A

→Melanocytes increase activity

→ They make and transmit more melanin

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14
Q

What 2 things happen to protect against UV?

A

→ Tanning

→ Skin thickening (Slowly)

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15
Q

Describe the process of tanning

A

→ UV light shines on keratinocytes and damages the DNA if there isn’t enough melanin
→ MSH gets produced by the keratinocytes
→ MSH binds to its receptor
→ It signals the cAMP pathway
→ More melanin is produced
→ Melanosomes go into the keratinocytes and build up the cap

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16
Q

What is tanning set off by?

A

→ DNA damage

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17
Q

Where are Langerhans cells found?

A

→ In the non basal layers of the skin

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18
Q

What is the function of Langerhans cells?

A

→ Antigen presenting cells

→ form a network in the epidermis

19
Q

What is lichenification and how does this occur?

A

→ more extreme hyperkeratosis

→ Reaction to excessive rubbing or scratching

20
Q

What are the 3 types of UV rays?

A

→ UVA and UVB (hit earth)

→ UVC (stopped by ozone)

21
Q

What type of burn is sunburn?

A

→ A radiation burn

22
Q

What happens during sunburn?

A

→ Blisters
→ Inflammation
→ Cell death

23
Q

What is sunburn associated with?

A

→ Risk of cancer

24
Q

What is a polymorphic light eruption?

A

→ Being allergic to sunlight

→ Rash when out in the sun

25
Q

What are naevi?

A

→ a benign proliferation of melanocytes

26
Q

What do many naevi mean?

A

→ Risk factor for melanoma, skin cancer

27
Q

What are freckles linked to?

A

→ Red/fair hair

→ MC1R gene variants

28
Q

What are solar lentigos?

A

→ Liver/Age spots

29
Q

What are solar keratoses?

A

→ Dysplastic growth of keratinocytes

30
Q

What cells does melanoma affect?

A

→ melanocytes

31
Q

What cells does non-melanoma affect?

A

→ keratinocytes

32
Q

What are the two types of non-melanoma cancers?

A

→ Squamous cell carcinoma

→ Basal cell carcinoma

33
Q

What are the characteristics of basal cell carcinoma?

A

→ It doesn’t spread easily

→ Often curable by surgery

34
Q

What is UV needed for?

A

→ Vitamin D3 production in the skin

35
Q

What are the three types of burn?

A

→ Superficial
→ Partial thickness
→ Full thickness

36
Q

When does irritant contact dermatitis occur?

A

→ Too much exposure to a substance

37
Q

What are the symptoms of irritant contact dermatitis?

A

→ Redness, itching, swelling, blistering

38
Q

What is allergic contact dermatitis?

A

→ Allergy to something that contacts the skin

→ Small amount is sufficient

39
Q

What are the steps to allergic contact dermatitis?

A

→ Sensitisation first : Langerhans cells process antigen and present it to the lymphocytes
→ Delayed hypersensitivity occurs at the next exposure

40
Q

What is paronychia?

A

→ Nail fold infection

→ Can be fungal or bacterial

41
Q

What is tinea capitis?

A

→ Scalp ringworm

42
Q

What is impetigo?

A

→ an injury getting infected

43
Q

Where can microbes enter?

A

→ In a breach in the epidermis