Skin Flashcards

1
Q

What is the epidermis layer of skin composed of

A

Primarily of keratinocytes

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2
Q

What is the dermis layer of skin composed of

A

Mainly connective tissue

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3
Q

What is the hypodermic layer of skin composed of

A

Subcutaneous layer/fat layer
Mainly adipose tissue

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4
Q

What are the 3 layers to skin

A

Epidermis
Dermis
Hypodermis

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5
Q

What is differentiation

A

Process in which cell changes from one cell type to another

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6
Q

What is stratification

A

Squamous epithelial cells arranged in layers upon a basement membrane

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7
Q

What are the 4 structural layers of the epidermis

A

Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum

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8
Q

What epithelium is the epidermis layer

A

Specialised stratified squamous

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9
Q

What protein does the epidermis contain

A

Cytokeratin proteins

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10
Q

What makes up 90% of cells

A

Keratinocytes

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11
Q

How does the epidermis layer adhere to one another

A

By desmosomes - a cytoskeleton attachment junction connecting cells to one another in epithelia and muscle tissues

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12
Q

How does the epidermis adhere to basement membrane

A

Via hemidesmosomes

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13
Q

What is the stratum corneum layer

A

Desquamating keratinocytes layers of flattened non nucleated cells provide a barrier against trauma and infection

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14
Q

What is the granular cell layer

A

Lipids produced by keratinocytes are secreted into the ECM spaces and forma barrier that retains water in the skin

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15
Q

What is the spinous layer

A

Appearance due to a combination of desmosome junctions which join keratinocytes and cell shrinkage

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16
Q

What is the basal layer

A

Site of stem cells high rate of cell division keratinocytes divide here before moving laterally then ascending

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17
Q

How does stratum spinosum work

A

As cells commit to terminal differentiation they increase in size and switch from the expression of cytokeratin proteins K14/K5 to K1/K10

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18
Q

What type of collagen is basement membrane

A

Type IV collagen

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19
Q

What 4 items does the basement membrane consist of

A

Laminin
Collagen
Fibronectin
Hemidesmosomes - integrins

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20
Q

What do melanocytes protect against

A

UV radiation and ROS

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21
Q

What do melanocytes not contain

A

Desmosomes

22
Q

Where are dendritic cells found

A

In the mid layer of the epidermis

23
Q

Which type of cell is non dendritic

A

Merkel cells

24
Q

What are merkel cells

A

Basal distribution
Associated with nerve fibres
Sensory function
Contain small, membrane bound vesicles release neurotransmitter
Contain cytokeratins
Desmosomes attach them to keratinocytes

25
Q

What are langerhans cells associated with

A

Presentation of antigens to sensitised T lymphocytes significant role on pathogenesis of delayed type hypersensitivity states

26
Q

Where are lymphocytes found

A

In mucosal epithelia (e.g oral and gut)

27
Q

What do mast cells do

A

Important in the pathogenesis of immediate type hypersensitivity response

28
Q

What are the 2 layers of the dermis

A

Papillary dermis
Reticular dermis

29
Q

What is the papillary dermis composed of

A

Loose areolar connective tissue

30
Q

What is the reticular dermis composed of

A

Dense irregular connective tissue

31
Q

What does the dermis layer contain

A

Blood and lymph vessels and nerves supplying the skin and adnexal structures

32
Q

What is the principle cell type in the dermis

A

Fibroblast

33
Q

What is the hypodermis (subcutaneous layer)

A

Fat layer insulates the body serves as energy supply allows for mobility

34
Q

What are 4 adnexal structures

A

Hairs
Erector pili muscles
Sebaceous glands
Sweat glands

35
Q

What is eccrine

A

Major sweat glands do not involve hair follicle

36
Q

What is apocrine

A

Associated with hair follicles secret a fatty mixture into the gland tubule

37
Q

What are sebaceous glands stimulated by

A

Androgens and inhibited by estrogen
They are lipid filled cells

38
Q

What do pecinian corpuscles sense

A

Deep pressure
Fast vibrations

39
Q

What do meisners corpuscles sense

A

Light tough
Slow vibrations

40
Q

What do free nerve endings sense

A

Temp, touch, pain

41
Q

What do merkels disks sense

A

Sustained pressure
Hairless skin

42
Q

What does dry epidermis cause

A

Reduction in sebaceous gland activity

43
Q

What do fewer melanocytes cause

A

Paler skin
Reduced tolerance to sun exposure

44
Q

What does thin dermis cause

A

Sagging and wrinkling due to collagen and elastin fibre loss

45
Q

What does a thin epidermis cause

A

Slower repair
Decreased vitamin D production
Reduced number of langerhans cells

46
Q

What does VUB (290-320nm) do

A

Damaging melanocytes, keratinocytes and causes the production of proteolytic enzymes

47
Q

What does UVA (320-400nm) do

A

Penetrates deeper than UVB exerts direct effect on both dermis and epidermis

48
Q

Which is the most common skin cancer

A

Non melanoma

49
Q

In what layer are stem cells mainly found

A

The basal layer

50
Q

Do epithelial cells have a blood supply

A

No