8. Integument Flashcards

1
Q

What classification of epithelial tissue is seen in the epidermis?

A

Keratinized stratified squamous

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2
Q

What embryological structure gives rise to melanocytes?

What is the clinical relevance of this geneology?

A

Neural Crest

When melanocytes become cancerous (melanoma), the neural crest’s desire to migrate gets turned on. Therefore melanomas are likely to metastasize.

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3
Q

Where are melanocytes found?

A

Stratum Basale

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4
Q

Why might superficial Stratum Corneum cells be less able to attach to one another than deeper cells of the epidermis?

A

Because the lowered pH is unfavorable to cell junctions

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5
Q

What nail cell divides to form the majority of the nail?

A

Nail Matrix stem cells

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6
Q

Where might the dermal epidermal junction be more “zippered?”

A

Areas of increased mechanical stress

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7
Q

Where do we find the erector pili muscles?

A

In the Hypodermis

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8
Q

In what layer of the dermis are you likely to find more vasculature and nerve endings?

A

The papillary layer

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9
Q

What would we find in the medulla of a hair follicle?

A

Large, loosely connected, keratinized cells

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10
Q

In what layer of the eipdermis would we find “squames?”

A

Stratum Corneum

(This is what some people refer to the flat corneal cells as)

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11
Q

Cells of the Stratum Corneum do not have nucleii or organelles, what other layer of cells in the epidermis shares this description?

A

Stratum Lucidium

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12
Q

How do keratinocytes uptake melanin?

What is the term for this action?

A

They phagocytose it

Pigment donation

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13
Q

What is the function of a Pacinian Corpuscle?

A

Detecting pressure and vibration

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14
Q

What layer of the skin can be described as containing “polyhedral keratinocytes?”

A

The Stratum Spinosum

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15
Q

What does “desquamation” mean?

A

Means that cells will be sloughed off of the surface due to contact with the outside world.

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16
Q

Where is the water barrier of the epidermis primarily found?

A

Between the cells of the Stratum Granulosum and the Stratum Corneum

(It also exists between the layers of the Stratum Corneum)

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17
Q

Why does the Stratum Granulosum appear so dark purple on a normal stain?

A

Because keratohyalin granules are basophillic

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18
Q

What would we find in the Cortex of a hair follicle?

A

Hard keratinized cells and intermediate filaments

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19
Q

What are Langerhans Cells?

A

Antigen presenting macrophages that provide defense from pathogens

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20
Q

What do sebaceous glands secrete?

A

Sebum

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21
Q

Where does the initial melalanin production occur within a melanocyte?

A

The Premelanosomes

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22
Q

What layer of skin can only be seen in thick skin?

A

Stratum Lucidium

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23
Q

What do Langerhans Cells develop from?

A

Monocyte precursor

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24
Q

Where in the dermis would you find thicker collagen fibers and course elastic fibers?

A

The Reticular layer

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25
Q

Where does melanin sit in the nucleus of a keratinocyte?

A

As a “dark umbrella” over the nucleus

(How is Dark Umbrella not the name of a goth rock band?)

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26
Q

What binds the most basal cells of the stratum basale to the dermis?

A

Hemidesmosomes

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27
Q

What is the thickest layer of the non-keratinized portion of the epidermis?

A

Stratum Granulosum

(These cells produce karatin precursors to the layers above them)

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28
Q

What is a “cornified” cell?

A

A cell that is full of keratin

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29
Q

What do you call the protrusions of epidermis into the dermis?

A

Epidermal Rete or Ridges

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30
Q

What is the Lunula?

A

The crescent shaped white part at the base of the nail, near the nail matrix

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31
Q

What causes fingerprints?

A

Dermal Ridges of thick skin

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32
Q

What induces an epidermal cell to loose its nucleii and organelles?

A

Lowered pH

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33
Q

Where might you find a Meissner’s Corpuscle?

A

In the dermis, close to the epidermis

34
Q

What allows you to detect fine touch, heat, cold, and pain in the skin?

A

Free nerve endings

35
Q

What sort of secretion do Apocrine Sweat Glands use?

A

Merocrine secretion

(despite the name)

36
Q

Why is the Stratum Lucidium named as such?

A

Because it appears “clear” relative to other layers.

37
Q

Which sweat glands are activated during puberty?

A

Apocrine sweat glands

38
Q

What sort of regulation to Apocrine Sweat Glands respond to?

A

Adrenergic

(adrenaline)

39
Q

Where would you find a Pacinian Corpuscle?

A

In the juction between the dermis and the hypodermis, sometimes as deep as the fat.

40
Q

What are Langer’s Lines?

Where are they found?

A

Regular lines of bundled collagen fibers as a response to the direction of stress

Found in the reticular layer of the dermis

41
Q

What part of the melanocyte extends into the cell processes?

A

The melanosome

42
Q

Which layer of the dermis lies directly under the epidermis?

A

Papillary layer

43
Q

Where can Merkel Cells be found?

A

Stratum Basale

44
Q

What is the cuticle?

A

The extension of skin covering the nail root.

45
Q

How is the melanin producing enzyme induced to produce more melanin?

A

It is UV sensitive

46
Q

What about apocrine sweat glands makes them produce odor when mixed with bacteria?

A

The merocrine secretion they release is high in carbohydrates

47
Q

What part of the hair follical is invaginated by the dermal papillae?

A

The bulb

48
Q

What is another name for the hypodermis?

A

Subcutaneous fascia

49
Q

What rapidly dividing cells accout for hair growth?

A

Matrix cells

50
Q

What layer of the skin is constantly shed?

A

Stratum Corneum

51
Q

What four main cell types are contained in the Stratum Basale?

A

Keratinocytes

Stem Cells

Melanocytes

Merkel Cells

52
Q

What sort of epithelium do we see in the ducts of sweat glands?

A

Stratified cuboidal

53
Q

Where in the layers of the epidermis might you find cuboidal cells?

A

The most basal layer of the Stratum Basale

Throughout in the ducts

54
Q

What are the characteristics covered in lecture for Merkel Cell Carcinoma?

A

Very rare

Highly Aggressive

55
Q

Where can one identify Langerhans Cells?

A

In the Stratum Spinosum

56
Q

What is the name of the adipose tissue of the hypodermis?

A

Panniculus Adiposus

57
Q

What are the 5 layers of the epidermis from top to bottom?

A

Stratum Corneum

Stratum Lucidum

Stratum Granulosum

Stratum Spinosum

Stratum Basale

_C_ome _L_ets _G_et _S_un _B_urnt

Jon is not allowed to use this mnemonic**!

58
Q

What two important compounds are found in the granules of the Stratum Granulosum?

A

Keratohyaline Granules

Filaggrin to assemble the keratin into bundles

59
Q

What is an epidermal-melanin unit?

A

A melanocyte and the ≈36 keritinocytes that it transfers melanin to.

60
Q

What binds the apical sides of the keratinocytes of the Stratum Basale?

A

Desmosomes

61
Q

What type of secretion do sebacious glands use?

A

Holocrine secretion

62
Q

What do we call an extension of the dermis into the epidermis?

A

A Dermal Papilla

63
Q

What are Meissner’s Corpuscles?

A

“Footprint” looking structure perpindicular to the skin’s surface that respond to low frequency stimuli - not vibrations

64
Q

What sort of regulation do we see in Eccrine Sweat Glands?

A

Cholinergic regulation

65
Q

What cells provide “acute sensory perception” for light touch?

A

Merkel Cells

66
Q

What do myoepithelial cells do?

A

Squeeze sweat glands to release the sweat product

67
Q

Where would the Stratum Lucidum be present?

A

Palms and Soles of the Feet

68
Q

Where are Apocrine sweat glands found?

A

Axilla, areola, nipple, skin of the anus, external genitalia

69
Q

Where are Eccrine sweat glands found?

A

All over the surface of the skin, except the lips and external genitalia

70
Q

Which layer of the skin thickens with pressure to form corns and calluses?

A

The Stratum Spinosum

71
Q

What changes define a cell of the Stratum Corneum as we travel up through the layers?

A

Loss of organelles

Becoming full of mature keratin

72
Q

What would you find at the core of a pacinian corpuscle?

A

A Myelinated Neuron

73
Q

What is different about the karatinocytes of the Stratum Granulosum, relative to the keratinocytes of the Strata Basale and Spinosum?

A

They start producting visable granules - the others produce precursors

74
Q

What is it about the plasma membrane of Corneal Cells that makes them such a good water barrier?

A

Their plasma membrane is coated with a layer of lipids from the lamellar bodies of the Stratum Granulosum

75
Q

What is vellus hair?

A

The thin white hairs that grow on the body before terminal “post-pubescent” hairs replace them.

(Eg, the hairs of the face that forced some people to shave -or just look kind of ratty - well before they could actually grow a beard)

76
Q

Which of the layers of the dermis includes the dermal papilla?

A

Papillary layer

77
Q

What do we call the bundles of keratin filaments in the basal layer?

A

Tonofibrils

78
Q

Where in the dermis are you likely to find a layer of loose areolar connective tissue?

A

Between the papillary layer and the epidermis

79
Q

Why do surgeons cut along Langer’s Lines?

A

It promotes wound healing

80
Q

What are the two steps of the production of melanin listed in the lecture?

A

Tyrosine -> DOPA (tyrosinase)

DOPA -> Melanin (polymerization)

81
Q

What detects movements of hair?

A

Free Nerve Endings