Skin layer overview Flashcards

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1
Q

What are the 3 layers of the skin?

A

epidermis, dermis, subcutis

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2
Q

What are the primary skin cells of the epidermis?

A

keratinocytes (primary), melanocytes, langerhans, Merkel cells

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3
Q

What is an important feature the epidermis lacks?

A

no blood vessels or nerve endings

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4
Q

What layer is primarily made of fibroblasts, collagen, and elastic cells?

A

dermis

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5
Q

If you were to bleed from a pencil stick, what layer are you in at minimum?

A

dermis

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6
Q

What layer of skin contains the fat?

A

subcutis

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7
Q

What is also found in the subcutis layer?

A

blood vessels and fibrous septae

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8
Q

What is the primary job of the epidermis?

A

primary barrier fxn, protection, and wound healing

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9
Q

What are the jobs of teh dermis and subcutis?

A

structural support, vascular support, innervation

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10
Q

How long does it take for a new epidermal layer to grow?

A

28+ days

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11
Q

What part of the epidermis do stem cells grow?

A

basal layer (shed from surface)

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12
Q

Describe the differentiation of the stem cells from the basal layer

A

cells terminally differentiate as they move upward

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13
Q

What is the order of the layers in the epidermis? (outside-in)

A

corneum, granulosum, spinosum, basale

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14
Q

What is important about hemidesmosomes?

A

basal cells adhere to the dermis (basement membrane zone) via hemidesmosomes

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15
Q

As the cells that are migrating from the basale layer to the spinous layer, what is important about their growth?

A

they stop dividing and start terminal differentiation

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16
Q

As the cells of the spinous layer develop, what improves the barrier function of the skin?

A

develops lipid from lamellar granules

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17
Q

Where are desmosomes located?

A

spinous layer of the skin

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18
Q

What is the function of the desmosomes?

A

spiny cells that adhere the KC to one another

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19
Q

The granular cell layer synthesizes what to be used in the outer cell layers?

A

profilaggrin

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20
Q

What type of granules are synthesized in the granular cell layer?

A

intracellular keratohyaline granules

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21
Q

What would be histologically prevalent of the stratum corneum?

A

nuclei and organelles degenerate, cells flatten

22
Q

Another water barrier is in the stratum corneum. Describe it

A

profilaggrin processed into filaggrin that combines with keratins to form macrofibrils creating a protective layer

23
Q

T/F stratum corneum is different at different locations throughout the body

A

true

24
Q

What are the bricks of the stratum corneum?

A

flattened keratinocytes filled with keratin and filaggrin

25
Q

What is the mortar of the stratum corneum?

A

lipid mix surrounding keratinocytes providing a water barrier

26
Q

What forms the intermediate filaments?

A

keratins combining

27
Q

What is significant about keratin and its function?

A

pairs differently to stabilize the cell against stress (different in different locations)

28
Q

Melanocytes produce pigment. Where are they derived from? What is their function?

A

neural crest cells=> transfer melanin to surrounding keratinocytes

29
Q

Where are melancocytes found?

A

living with the basal cells and stretching into the spinosum layer

30
Q

Which skin cell is important in allergic reaction AND tumor/antigen surveillance? where does it live?

A

Langerhans cells and mid-epidermis

31
Q

What is an epidermal cell that that is associated with light touch sensation?

A

Merkel cells

32
Q

What is the primary function of the dermis?

A

support layer that varies in thickness

33
Q

What structures can be found in the dermis?

A

vasculature, nerves, sweat and oil glands, hair follicles

34
Q

What is the primary cell in the dermis? What is its origin?

A

fibroblasts and mesenchymal origin

35
Q

What is the responsibility of the fibroblasts in the dermis?

A

synthesis and degration of connective tissue proteins (collagen, elastin, GAGs)

36
Q

An injury to the skin triggers the mitotic activation of which cells?

A

fibroblasts (wound healing and scar formation)

37
Q

Which cells located in the skin are associated with wound healing and allergic reactions?

A

mast cells (wheal and flare rxn)

38
Q

Hair follicles extend through dermis into what? what does each follicle have associated with it?

A

hair follicles extend through dermis into subcutis and oil gland is associated

39
Q

What does the pilosebaceous unit consist of?

A

hair follicle, sebaceous gland, apocrine sweat glands, arrector pili muscle

40
Q

What are the “true” sweat glands and where are they?

A

Eccrine sweat glands are located throughout the body

41
Q

Where do the eccrine sweat glands open and what is their fxn?

A

open directly onto the skin and regulate temp by evaporative cooling of sweat

42
Q

What is the fat layer that separates the dermis from the underlying structures?

A

subcutis

43
Q

What is the role of the subcutis?

A

insulation, energy source, injury protection

44
Q

What is the normal response to sundamaged cells?

A

apoptosis of keratinocytes

45
Q

What occurs if the hemidesmosomes are damaged or altered?

A

Bullous pemphigoid

46
Q

If the desmosomes of the spinous layer are damaged, what is the result?

A

pemphigus vulgaris

47
Q

Genetic defects in filaggrin is assocated with what disease and what layer of the epidermis?

A

atopic dermatitis and stratum corneum

48
Q

What is a genetic mutation in keratin 5/14 associated?

A

epidermolysis bullosa simplex

49
Q

What will be the clinical Sx of epidermolysis bullosa simplex?

A

blisters due to K5/14 filament mutation not allowing the hemidesmosome and basal KC attachment

50
Q

What is a nevus?

A

Mole=> benign collection of melanocytes

51
Q

What is a melanoma?

A

growth of malignant melanocytes

52
Q

What are diseases that are associated with the subcutis?

A

panniculitis