Skin: moles and papules Flashcards

1
Q

What are the 3 layers of skin?

A

Epidermis

Dermis

Subcutaneous (hypodermis)

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2
Q

What embryological layer is the epidermis derived from?

A

Ectoderm

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3
Q

What type of cells are found in the epidermis?

A

(Keratised) Stratified squamous epithelium

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4
Q

What are the epithelial cells in the epidermis filled with?

What are some of the properties of this substance?

A

Keratin

A protein that is protective and insoluble.

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5
Q

What lies between the epidermis and the dermis?

A

Basement membrane

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6
Q

Which layer are hair follicles and sweat glands found in?

A

Dermis

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7
Q

Name the 2 layers of the dermis

A

Papillary - finger like projections into the epidermis

Reticular

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8
Q

What 5 things can be found in the dermis and not in the epidermis?

A

Collagen fibres

Elastin fibres

Blood vessels

Nerves

Lymphatic vessels

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9
Q

Why is the subcutis important in thermoregulation?

A

It is a rich adipose (fat) layer that acts as a reserve for energy resources

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10
Q

What fibres that can be found in the dermis degenerate with age and cause wrinkles?

A

Collagen

Elastin

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11
Q

Name the 4 layers of the epidermis from basement membrane upwards

A

Basal layer

Spinous layer

Granular layer

Cornified layer

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12
Q

Give some characteristics of the basal layer of the epithelium

A

Single layer of cells

Epidermal stem cells - constantly dividing to form keratinocytes.

Aim of keratinocytes is to form keratin and move up through the epidermis.

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13
Q

Give some characteristics of the spinous layer of the epithelium

A

Variable thickness - usually 3 cell layers

Contains keratin fibrils

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14
Q

Give some characteristics of the granular layer of the epithelium

A

Few cell layers thick

Contains granules that stain in histology

Keratin fibrils become fibres

CELLS LOSE NUCLEUS

Cells get coated by glycophospholipids that makes the cells water-proof

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15
Q

Give some characteristics of the cornified layer of the epithelium

A

Contains keratin

Cells have no nucleus but are waterproof (glycophospholipids)

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16
Q

What is the difference in the epidermis in patients with psoriasis?

A

The amount of time it takes for cells to move from the basal layer to the cornified layer is reduced

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17
Q

How are cells in the basal layer of the epidermis connected to the basement membrane?

A

Hemidesmosomes

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18
Q

What changes keratin fibrils into keratin fibres?

A

Keratohyalin granules

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19
Q

What releases glycophospholipids into the cornified layer of the epithelium?

What does this do to the cells?

A

Lamellar bodies

Makes the cells water-proof

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20
Q

What causes the dark colour of skin?

What is this formed by?

Which layer of the skin is this found in?

A

Melanin

Melanocytes

Basal layer of the epidermis

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21
Q

What is formed in the epidermis during histological preparation?

A

Desmosomes

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22
Q

Where are Merkel cells usually found?

A

In the basal layer of the epidermis

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23
Q

What do Merkel cells do?

A

They are in close proximity to the nerve endings and have a sensory function

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24
Q

Name a difference between ‘thick’ and ‘thin’ skin

A

Thick skin has a thick cornified layer and an additional stratum lucidum

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25
What type of hair is thin and can be found all over the body?
Vellus hair
26
What type of hair can be found on the skull, beard, pubic and axillary regions. What is it for?
Terminal hair Protection
27
What are hair follicles made from?
Keratin
28
As a hair follicle grows, what does it associate with?
A sebaceous gland Erector pilli muscles
29
Where is sebum secreted from?
Sebaceous glands
30
What 3 things make a pilosebaceous unit?
Hair follicle Sebaceous gland Smooth muscle
31
Which gland is affected in acne?
Sebaceous glands
32
What is the role of the eccrine sweat glands?
2 parts - secretory and duct Take up plasma filtrate and filter out electrolytes e.g. NaCl. Water is filtered out as sweat Concentration of sweat depends on hydration status of the patient
33
What is the role of the apocrine glands?
Under hormonal control Associated with hair in the axilla and groin region Secretion contains fats and proteins. Secretion does not smell until it comes into contact with bacteria on the skin's surface
34
What is the nail plate formed from?
Keratin
35
Describe the blood supply to the skin
Veins and arteries form 2 plexi: A cutaneous (deep) pleuxus between the subcutis and the dermis and A superficial plexus between the dermis and the epidermis The epidermis itself has no blood vessels going through it
36
If a skin lesion is flat, can be seen but is not palpable, what is it called? What term would be used to describe a larger area of a flat lesion?
Macule A patch
37
If a skin lesion is flat, can be seen but is not palpable, what is it called? What term would be used to describe a larger area of a flat lesion?
Macule <5mm A patch
38
If a skin lesion is raised and solid, and less than 5mm in size, what is it?
Papule
39
If a skin lesion is raised and solid, and more than 5mm in size, what is it?
Nodule
40
Give an example of a malignant papule/nodule (depending on size)
Basal cell carcinoma
41
If a skin lesion is raised, can be felt, but the area is greater than the height, what is it?
Plaque
42
Where are plaques normally found? Give a common example of a plaque
Extensor surfaces e.g. elbow/knee region Psoriasis
43
What happens to the keratinocytes in psoriasis? And the epidermis in general?
They become larger and become nucleated - become porokeratosis Blood vessels become more superficial
44
If a skin lesion is raised, filled with clear serous fluid, and <5mm, what is it?
Vescile
45
If a skin lesion is raised, filled with clear serous fluid, and >5mm, what is it?
Bullae
46
If a skin lesion is raised and filled with pus, what is it?
Pustule
47
Which conditions can present with vesicles/bullae?
Herpes zoster Shingles Chicken pox
48
What is a neoplasm?
A lesion resulting from the autonomous growth of cells in the absence of a stimulus
49
Describe the appearance of a benign neoplasm
Slow expansive growth Symmetrical Capsule present Resembles tissue of origin Differentiated cells Smooth surface
50
Describe the appearance of a malignant neoplasm
Fast, invasive, metastatic growth Crab-like appearance No capsule Does not resemble tissue of origin Undifferentiated cells Irregular surface, may ulcerate and haemorrhage
51
Name the 3 forms of skin cancer
Basal cell carcinoma Squamous cell carcinoma Malignant melanoma
52
What is the key prognostic factor in skin cancer diagnosis?
Depth of invasion
53
Discuss basal cell carcinoma (BCC)
Commonest form of skin cancer in the UK Slow growing Usually does not metastasise but can become locally destructive
54
Name 3 risk factors for BCC
UV radiation exposure Immunosupression Inherited conditions e.g. xeroderma pigmentosum
55
Describe the appearance of a BCC
Slow growing Can be superficial or nodular Rolled edge Punctum in middle +/- abscess Associated with blood vessels Slowly eating away at the skin Usually located in sites where there is little surplus skin to repair site when removed
56
Identify the risk factors for squamous cell carcinoma (SCC)
UV radiation Male sex Fair skin Occupational exposures; tars, oil, radiation Immunosupression
57
Describe the appearance of a SCC
Often still able to produce keratin - may be a crust on top of the lesion Can present as 'non-healing ulcer'.
58
Name some histological changes in SCC
Hyperchromatism Pleomorhphism High nuclear:cytoplasmic ration Loss of normal tissue architecture Changes can be seen prior to invasion - 'carcinoma in situ'
59
Where is a carcinoma in situ contained?
Within the epidermis/epithelial layer of a tissue
60
What is the ABCDE criteria of assessing a skin lesion?
Asymmetry Border Colour Diameter Evolving
61
Name some risk factors of malignant melanoma
UV radiation exposure - patterns of exposure e.g. childhood exposure FH of melanoma Presence of dysplastic or abundant naevi
62
What does the stage of a cancer mean?
The size of the tumour and how far it has spread from where it originated
63
What does the grade of a cancer mean?
The appearance of the cancerous cells
64
What is the TNM staging for cancers?
Tumour size (DEPTH) Lymph node involvement Metastases