Derm - 2-23 - Epidermis And Dermis

Front 1

Keratinocyte types

Back 1

Stem cells

Transient amplifying cells - a little more diff than the stem cells.

Term diff cells.

Front 2

Keratinocyte adherence proteins

Back 2

Desmosomes - Holds keratinocytes together.

Hemidesmosomes - Glues down basal layer of cells to the BM.

Front 3

Keratin types

Back 3

They are intermediate filaments.

Type I - Acidic - K9-20

Type II - basic - K1-8

***the letter B looks like an 8...that is where it ends.

Front 4

Melanocytes derived from...

Back 4

neural crest

Front 5

Langerhans cell arise from...

Back 5

bone marrow.

They can go to LN from epidermis and present an antigen.

Look clear in histology.

Front 6

Merkel cell

Back 6

epidermins.

Neuroendocrine, important for touch.

Merkel cell carcinoma is very aggressive.

Front 7

Dendritic epidermal T cell

Back 7

Has gamma-delta TCReceptor.

Homeostasis and skin immunity.

Front 8

Where in epidermis does cell division occur?

Back 8

stratum basale.

Front 9

Epidermal turnover time

Back 9

28 days normally.

Takes 14 days from basale to corneum and 14 days from corneum to sloughing.

Front 10

Difference in back and palms.

Back 10

Corneum is a lot thicker and stratum lucidum is present above the granulosa layer in palms and soles of feet.

Front 11

What does granulosa layer look like?

Back 11

darker and pigmented.

Front 12

Basal cell layer contains...

Back 12

hemidesmosomes and has a high mitotic rate.

tonofilaments synth here.

Front 13

spinous cell has cells that are...

Back 13

differentiating

tonofilaments aggregate into tonofibrils and desmosomes are present here.

Front 14

granular cell layer

Back 14

A transitional zone where the keratinocytes contain keratohyaline and lamellar granules

Front 15

Corneal cell layer

Back 15

a thick cell envelope with lipids to protect the skin

contains dead cells, filaments too.

Front 16

keratinization is synonymous with..

Back 16

cornification

Front 17

Which keratin forms are expressed when?

Back 17

Basal - K5 and 14

Spinosum and granulosum - K1, 5, 10, 14

Corneal - K1 and 10

Front 18

Keratin synth

Back 18

coiled-coil triple helical protein with many cysteines.

Forms tonofilaments and then IFs.

Aggregates with filaggrin from keratohyaline granules to form macrofibrils which are secured to the cornified cell envelope.

Acidic and basic keratins pair together.

Front 19

Keratohyalin granules

Back 19

in granular layer.

CONTAIN FILAGGRIN!!! this causes aggregation of keratin filaments and gives stability.

Front 20

Cornified cell envelope

Back 20

thick band inside plasma membrane that gives strength and integrity of the stratum corneum.

Made via epidermal transglutaminase which crosslinks lysine

Front 21

External lipid layer

Back 21

Forms a permeability barrier and surrounds cells.

Made from lamellar bodies in the stratum granulosum

Front 22

Keratinization summary

Back 22

Keratohyaline granules - filaggrin

Cornified cell env - epidermal transglutaminase

Lamellar bodies - external lipid layer

Front 23

Ichthyosis vulgaris

Back 23

Defect in filaggrin

AD; 1% of population

Fine white scaling but spares flexures and has normal epidermal transit time.

Front 24

X-linked ichytosis

Back 24

XLRecessive.

steroid-sulfatase deficiency.

Flexural areas spared.

Corneal opacities.

Brown scales.

Front 25

Lamellar ichthyosis

Back 25

AR

Collodian baby - thick membrane on them when born.

Large thick scales with bacterial colonization. Almost looks like an alligator.

Defect in transglutaminase.

4 day transit time.

Front 26

Epidermolytic hyperkeratosis

Back 26

AD

Shed large areas of epidermis.

Vesicles and bullae develop and a thick verrucous scale covers the body.

Rapid epidermal transit time.

Mutation in K1 and 10.

Tire-tread appearance of skin.

Front 27

Acquired ichthyosis

Back 27

Drugs, systemic disease, malignancy

Front 28

Tx of ichthyoses

Back 28

Emollients - petroleum or creams

Keratolytics - decrease thickness of the skin (lactic acid, salicylic acid, urea, propylene glycol)

Retinoids - control differentiation of keratinocytes (aceitretin or isotretinoin)

Aniproliferative agnets (MTX)

Front 29

Cells of the dermis

Back 29

Fibroblasts, macrophages, mast cells.

Both layers have lymphatics and innervation

Front 30

Cells of the epidermis.

Back 30

Keratinocytes, melanocytes, langerhans cell, merkel cell, dendritic epidermal T cells (gamma-delta)

Front 31

Papillary dermis

Back 31

Type III collagen, cellular and horizontal vascular plexus.

Front 32

Reticular dermis

Back 32

Bulk of dermis, type I collagen and vertical vessels.

Front 33

Where are fibroblasts found?

Back 33

near collagen and elastic fibers

Front 34

Collagen synth

Back 34

Alpha chains (procollagen) forms in RER then there is hydroxylation, glycosylation. Then three alpha chains form a triple helix trimer. This is secreted into EXspace and proteases cleave it to make the collagen assemble.

Front 35

Ehlers-Danlos

Back 35

Hyperextensible skin

Due to collage defect. Results in atrophic scars.

Front 36

Gorlin sign

Back 36

Seen in Ehlers-Danlos

Hyperextendable skin and joints.

Ability to touch nose with tongue lip.

Front 37

Hypertrophic scar

Back 37

Within confines of the scar but just really thick.

Collagen disorder

Front 38

Keloid

Back 38

Spreads beyond the confine of a scar.

Collagen disorder

Front 39

Dermatofibrosarcoma protuberans

Back 39

Low grade malig proliferation of fibroblasts.

Appears as a wide local excision

Front 40

Morphea

Back 40

Localized scleroderma.

First red then indurated and atrophic plaques.

Front 41

Elastic fibers

Back 41

Made of elastin (desmosine/isedesmosine) and fibrillin (forms the framework for elastin)

Front 42

Cutis Laxa

Back 42

AD or AR or acquired.

Results in loosely hanging skin because of defective elastin prod.

Front 43

Pseudoxanthoma elasticum

Back 43

AD or AR.

Degen of arterial elastic fibers leads to occulsion and rupture.

Chicken skin appearance in side of neck.

Front 44

Mucopolysaccharides

Back 44

Maintains salt and tisue water balance.

It is a polysacch linked to protein.

Found in the dermis.

Pretibial myxedema is due to too much of it.