1. epidermis 2. dermis 3. subcutaneous fat (hypodermis or subcutis )

histology and terminology of skin/epitelial cell junction/pigmented skin disorders Flashcards by Anthos Christofides

skin has … (number) layers

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skin layers:

epidermis
dermis
subcutaneous fat (hypodermis or subcutis )

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subcutaneous fat of skin is also called 3

hypodermis or subcutis

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epidermis layers - from surface to base (only the names)

stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
statum basale

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epidermis layers - statum corneum is characterised by

keratin in anucleated cells

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epidermis layers - stratum lucidum is characterised by

dead skin cells

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epidermis layers - stratum granulosum is characterised by

granules in keratinocytes

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epidermis layers - stratum spinosum is characterised by

desmosomes between keratinocytes

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epidermis layers - stratum basale is characterised by

stem cells

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skin function

barrier against environmental insults and fluid loss

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dermis is seperated by epidermis by

basement membrane

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dermis consists of

connective tissue, nerve ending, blood and lymphocyte vessels, adnexal structures

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dermis - adnexal structures

hair shafts, sweat glands, sebacous glands

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adnexal structures in greek

εξαρτηματικές δομές

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epidermis layers - desmosomes between keratinocytes

stratum spinosum

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epidermis layers - granules in keratinocytes

stratum granulosum

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epidermis layers - dead skin cells

stratum lucidum

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hyperkeratosis - definition

increased thickness of stratum corneum

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examples of hyperkeratosis

psoriasis

2. calluses

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parakeratosis - definition

hyperkeratosis with retention of nuclei in stratum corneum

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parakeratosis - example

psoriasis

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spongiosis - definition

epidermal accumulation of edematous fluid in inter-cellular spaces

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spongiosis - example

eczematous dermatitis

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acantholysis - definition

hypergranoulosis - definition

acantholysis: seperation of epidermal cells
hypergranoulosis: increased thickness of stratum granulosum

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acantholysis example | hypergranoulosis - example

acantholysis: pemphigus vulgaris hypergranoulosis: liches planus

acanthosis - definition

epidermal hyperplasia (increased spinosum)

acanthosis - example

acanthosis nigricans

patch - definition

flat lesion with well-circumscribed change in skin color, >1 cm (macule but >1cm)

macule -definition

flat lesion with well-circumscribed change in skin color less than 1 cm

patch example

large birthmark (congenital nevus)

papule - definition

elevated solid skin lesion

papule example

1. mole (nevus) | 2. acne

plaque - definition

elevated solid skin lesion more than 1cm (papule but more than 1cm)

plaque - example

psoriasis

vesicle - definition

small fluid containing blister less than 1 cm

bulla - definition

large fluid containing blister more than 1cm

bulla example

bullous pemphigoid

vesicle - examples

chickenbox (varicella) | shingles

wheal - definition

transient smooth papule or plaque

wheal - example

Hives (urticaria)

pustule - definition

vesicle containing pus

pustule - example

pustular psoriasis

scale - definition

flaking off of stratum corneum

scale - example

eczema psoriasis SCC

crust - definition

dry exudate

crust - example

impetigo

transient smooth papule or plaque - terminology

wheal

dry exudate in skin - terminology

crust

epidermal hyperplasia (increased spinosum) - terminology

acanthosis

increased thickness of stratum granulosum - terminology

hypergranulosis

Epithelial cell junctions - types (from apical to basolateral nmz) and there other names

1. Tight junction (zonula occludens) 2. Adherens junction (belt desmosome, zonule adherens) 3. Desmosome (spot desmosome, macule adherens) 4. Gap junction 5. Hemidesmosome 6. Integrins

Epithelial cell junctions - tight junctions are also called

zona occludens

Epithelial cell junctions - tight junctions are composed of

claudins and occludins

Epithelial cell junctions - tight junctions - function

prevents paracellular movement of solutes

Epithelial cell junctions - adherent junction location

below tight junction

Epithelial cell junctions - adherent junction function/structure

forms belt connecting actin cytoskeleton of adjacent cells with cadherins (E-cadherin and actin filaments)

Epithelial cell junctions - cadherins characteristic of their action

Ca2+-depended adhesion proteins

Epithelial cell junctions - loss of E-cadherins -->

metastasis

Epithelial cell junctions - Desmosomes are also called

macula adherens / spot desmosomes

Epithelial cell junctions - desmosomes - location

stratum spinosum

Epithelial cell junctions - desmosomes - function/structure

structural support via keratin interactions (keratin and demsoplakin)

disease associated with desmosomes

autoantibodies against desmosomes --> pemphigus vulgaris

autoantibodies against desmosomes -->

pemphigus vulgaris

Epithelial cell junctions - gap juctions - structure

connexons (channel proteins)

Epithelial cell junctions - gap juctions - function

permit electrical and chemical communication between cells

Epithelial cell junctions - hemidesmosomes - location

between basal cells and basement membrane

Epithelial cell junctions - hemidesmosomes - function

connects keratin in basal cells to underling membrane

Epithelial cell junctions - hemidesmosomes related disease

autoantibodies against hemidesmosomes --> bullous pemphigoid

autoantibodies against hemidesmosomes -->

bullous pemphigoid

Epithelial cell junctions - integrins - function/structure

membrane proteins that maintain integrity of basolateral membrane by binding to collagen and laminin in basement membrane

Epithelial cell junctions - desmosomes structure

keratin and desmoplakin

Epithelial cell junctions - adherens junction - structure

E-cadherin and actin filaments

pigmented skin disorders - types

1. Albinism 2. Melasma 3. Vitiligo

albinism - mechanism (not the causes)

normal melanocyte number with decreased production of melanin

causes of albinism

1. decreased tyrosinase activity 2. defective tyrosine transport 3. failure of neural crest cell migration during development

albinism increases the risk of

skin cancer

melasma is also called

chloasma

melasma (chloasma) appearance

hyperpigmentation

melasma is .... associated with ....

hyperpigmentation associated with pregnancy (mask of pregnancy) or OCP use

melsasma (chloasma) associated with pregnancy is also called

mask of pregnancy

vitiligo - appearance

irregular areas of complete depigmentation

vitiligo is caused by

autoimmune destruction of melanocytes

epithelial cell junction - zonula occludens

tight junction

epithelial cell junction - zonula adherens

adherens junction

epithelial cell junction - macula adherens

desmosome

spongiosis - definition

epidermal accumulation of edematous fluid in inter-cellular spaces

macule example

Frenkle | labial macule