The Structure and Function of the Skin Flashcards Preview

Dermatology > The Structure and Function of the Skin > Flashcards

Flashcards in The Structure and Function of the Skin Deck (122):
1

Where is the epidermis?

The outer layer

2

Describe the epidermis

Stratified cellular epithelium

3

Where is the dermis?

Beneath the epidermis

4

Describe the dermis

Connective tissue

5

Where does the epidermis come from and how does it form?

Ectoderm cells form a single layer periderm. This gradually increases in layers of cells and the periderm cells cast off

6

How is the dermis formed?

From mesoderm below ectoderm

7

What are melanocytes

Pigment producing cells

8

Where do melanocytes migrate from

The neural crest

9

What 5 things does the skin consist of?

Epidermis
Appendages
Dermo-epidermal junction
Dermis
Sub-cutis

10

Give 4 examples of Appendages

Nails
Hair
Glands
Mucosae

11

What is the majority of the epidermis made up of and what does it contain?

keratinocytes. It contains structural keratins

12

What are the 4 types of epidermal cell layers

Keratin
Granular
Prickle cell
Basal

13

How is the regulation of epidermal turnover controlled

Growth factors
Cell death
Hormones

14

In what two scenarios is there a loss of control in the epidermal turnover

Skin Cancer
Psoriasis

15

Histologically, what happens to the cells in psoriasis

They migrate

16

Where do keratinocytes migrate from?

The basement membrane

17

How thick is the basal layer

One cell thick

18

What type of cell makes up the basal layer

Small cuboidal

19

What is the main feature of the basal layer

It is highly metabolically active

20

What are there lots of in the prickle cell layer

desmosomes (connections)

21

What connects to desmosomes

Intermediate filaments

22

What is the granular layer made up of

2-3 layers of flatter cells
High lipid content

23

What is unusual about the cells in the granular layer

Cell nuclei are lost

24

What is the main function of the keratin layer

To provide a tight waterproof barrier to keep you from losing water

25

What common skin disease affects keratinocytes and what does it cause?

HPV - causes warts

26

Where are the mucosal membranes in the body

Eyes
Mouth
Nose
Genito-urinary tract
Gi tract

27

What are the 3 other types of epidermal cells

Melanocytes (basal & suprabasal)
Langerhans cells (suprabasal)
Merkel cells (basal)

28

At what stage do melanocytes migrate from the epidermis to the neural crest

In the first 3 months of foetal development

29

What are the organelles called that melanocytes contain

Melanosomes

30

What is the function of melanocytes

To convert tyrosine to melanin

31

What absorbs light

Melanin

32

How are melanosomes transferred to adjacent keratinocyte

Via dendrites

33

What do melanin caps protect?

The nuclear DNA in basal cells

34

What represents an autoimmune disease with loss of melanocytes

Vitiligo

35

What happens in Albinism

A genetic partial loss of pigment production

36

What happens in Nelson's syndrome

Melanin stimulating hormone is produced in excess by the pituitary

37

What is the function of Langerhans cells

Involved in the skin immune system

38

What is the appearance of Birbeck granules

Racket organelles

39

Where are Merkel cells found

Between keratinocytes and nerve fibres

40

What do Merkel cells act as

Mechanoreceptors

41

Describe Merkel cell cancer

Rare
Caused by viral infection
High mortality

42

What is there always next to a hair follicle

Adjacent sebaceous gland

43

What are the 3 phases of hair follicle growth

Anagen (growing)
Catagen (involuting)
Telogen (resting)

44

Describe Alopecia areata

Autoimmune hair loss

45

What 3 sections make up the nail plate

Ventral
Intermediate
Dorsal

46

What is the Dermo-epidermal Junction

The interface between epidermis and dermis

47

What does the dermo-epidermal junction play a key role in

Epithelial mesenchymal interactions
Support, anchorage, adhesion, growth and differentiation of epidermal cells
Semi-permeable membrane acting as barrier and filter

48

What are present in the dermo-epidermal junction

Lots of proteins, fibrils and keratins

49

What is an inherited disease of the DEJ?

Epidermolysis bullosa

50

What is an acquired disease of the DEJ

Pemphigus, pemphigoid, dermatitis herpetiformis

51

What is the difference between inherited and acquired diseases of the DEJ

Inherited is due to a mutation in one of the proteins in the DEJ
Axquired is due to auto-antibodies to proteins in DEJ

52

Describe Epidermolysis Bullosa dystrophica

Deformity of the hands and feet - the skin fuses as it tries to over heal causing fingers and toes to stick together

53

At what age does Bullous Pemphigoid occur

Any age

54

What are the two fibres found in the dermis

Collagen and Elastin

55

Name 5 cells found in the dermis

fibroblasts
Macrophages
Mast cells
Lymphocytes
Langerhans cells

56

Name the 5 components of the dermis

Cells (fibroblasts, macrophages, mast cells, lymphocytes, Langerhans cells)
Fibres (collagen and elastin)
Ground substance
Vessels
nerves

57

What do macrophages do?

Hunt for antigen presentation

58

What do lymphocytes do

Control immune reactions

59

What are 2 risk factors for photoaging

UV light and smoking

60

What happens to the collagen in photoaging?

Collagen gets depleted

61

Describe the blood supply in the skin

Greater than metabolic needs

62

What happens in photoaging

Collagen gets depleted

63

How is Bullous Pemphigoid controlled

With the use of steroids

64

Name the 5 components of the dermis

Cells (fibroblasts, macrophages, mast cells, lymphocytes, Langerhans cells)
Fibres (collagen and elastin)
Ground substance
Vessels
nerves

65

What is the main protein in the dermis

Collagen

66

What is the function of the fibroblasts

To secrete collagen

67

What is the function of macrophages

scavengers, antigen presentation

68

What is the function of mast cells

Chemical messengers

69

What 2 factors lead to photoaging

UV lights and smoking

70

What happens in photoaging

Collagen gets depleted

71

Are blocked lymphatics easy or difficult to treat?

Difficult

72

Describe the deep vascular plexus

It is horizontal

73

What is the term given to the overgrowth of the blood vessel population

Angioma

74

Where are angiomas often found

The face

75

What are angiomas associated with?

Epilepsy

76

What is seen histologically in an angioma

Dilated vascular spaces

77

What happens if there is no protein in the blood supply

You get oedema

78

What can cause infection in the lower leg

Blockage in the lymphatics

79

Are blocked lymphatics easy or difficult to treat?

Difficult

80

What are the 2 types of special receptors in the nerves of the skin and what do they do?

Pacinian (pressure)
Meissners (vibration)

81

What nervous system supplies the skin

The autonomic

82

Where are sebaceious glands found

Everywhere but the palms of the hands and soles of the feet

83

What is required for sweat glands to work

Motor nerve

84

Where are neurofibromatosis often found

Back, spine and brain

85

What is neurofibromatosis

Overgrowth of the nerve endings

86

What are the 3 types of skin glands

Eccrine
Sebaceous
Apocrine

87

What type of gland works to cool you down

Ecrine (sweat)

88

Over activity of which type of gland results in acne

Sebaceous

89

What are apocrine sweat glands dependent on

Androgen

90

Where are sebaceious glands found

Everywhere but the palms of the hands and soles of the feet

91

What are the functions of eccrine glands (3)

Cooling by evaporation
Moisten palms/ soles to aid grip

92

What are the main two functions of sebaceous glands

Control moisture loss and protect from bacterial and fungal infections

93

What is the main target of the treatment of acne

To target the oil gland to stop it secreting as much

94

When does odour occur from sweat

After bacterial decomposition

95

How do apocrine sweat glands develop

As part of pilosebaceous unit

96

Where are apocrine sweat glands located

Axillae and perineum

97

What are apocrine sweat glands dependent on

Androgen

98

What occurs in cumulative irritant hand dematitis

Extra fluid between epidermal cells which can be seen between vesicle cells

99

What are the functions of eccrine glands (3)

Cooling by evaporation
Moisten palms/ soles to aid grip

100

What are the 6 main functions of the skin

Barrier
Metabolism and detoxification
thermoregulation
immune defence
communication
sensory functions

101

What is Erythroderma largely made up of

Keratin loss or general protein loss (very dry appearance)

102

If the barrier is broken down, what happens

Dehydration
Hypoalbuminaemia
Infection

103

What is the 2 way barrier of the skin

Epidermis

104

What is the underlying cause of ichthyosis

Cholesterol not being properly metabolised

105

What can induce ichthyosis

Statins

106

What occurs in cumulative irritant hand dematitis

Extra fluid between epidermal cells which can be seen between vesicle cells

107

What happens in frostbite

There is so much vasocontstriction that the person has lost tissue

108

Describe the relationship between the wavelength of light and the depth of penetration into skin tissue

The longer the wavelength the deeper the penetration - more chance of skin cancer with deeper penetration as it can cause more damage

109

What does melanin do

Absorbs UV rays to protect DNA in the cells' nuclei

110

In which 3 ways is the skin metabolically active

Vitamin D metabolism
Thyroid hormone metabolism
Defence against chemicals, drugs, pollutatnts and sunlight

111

What is another name for crusted scabies

Norwegian scabies

112

Where does the conversion of Thyroxine T4 to Triiodothyronine T3 occur

Mostly (80%) in periphera (to thyroid)l tissues including skin and 20% in the thyroid

113

What does thermoregulation do

Protect against being too hot or too cold by controlling sweating, shivering and blood supply

114

What amount of sweat can be produced by 1 person in a day

20L

115

What happens in frostbite

There is so much vasocontstriction that the person has lost tissue

116

What are the 2 most important cells in the immune defence in the skin

Langerhans' and T cells

117

What are examples of non-specific immune defence responses

Itch, localised prickling

118

What are specific responses in immune defence

Memory response to some infection that you have previously been exposed to

119

What is another name for crusted scabies

Norwegian scabies

120

What is chronic discoid lupus erythematosus

An autoimmune disease which is caused by an inappropriate immune response

121

Name some types of sensory functions of the skin

Touch, pressure, vibration
Pain and itch
heat and cold
nerve endings and receptors in the skin

122

What condition is often associated with diabetes mellitus

Neuropathic ulcer (leprosy)