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FMS Week 5 > Skin > Flashcards

Flashcards in Skin Deck (23):
1

Epidermis

Forms major distinction between thick skin (palms and soles, 400 to 1400 micro M) and think skin (75 to 150 micro m) 

Lacks vasculature, but recieves nutrients and O2 by diffusion from dermis 

2

Layers of Epidermis: Top Down

 

Stratum Corneum

Stratum Lucidum

Stratum Granulosum

Stratum Spinosum

Stratum Basale 

3

Stratum Basale

Intense mitotic activity

Single layer of basophilic cuboidal or columnar cells at basement membrane at dermal epidermal junction

Hemidesmosomes in hte basal cell membranes join these cells to the basal lamina 

Desmosomes bind the cells of this layer together in their lateral and upper surfaces 

Durring differentiation, cells move upward 

4

Stratum Spinosum

Just above the basal layer

Thickest layer, esp in epidermal ridges 

Consists of generally polyhedral cells with cenral nuclei 

Desmosomes hold the cell layers together 

Thick skin subject to continuous friction and pressure (such as the foot soles) has a thicker stratum spinosum 

The most basal layer can be involved in repair 

5

Stratum Granulosum

Three to five layers flattened cells undergoing the terminal differentiation process of keratinization

 

Cytoplasm is filled with intensely basophilic masses (called keratohyaline granules and lamellar granules) 

Among the last activities of the keratinocytes, the lamellar granules undergo exocytosis, producing a lipid-rich, impermeable layer around the cells 

6

Stratum Lucidum

 

Only in thick skin

Consists of a thin, translucent layer of flattened eosinophilic karatinocytes held together by desmosomes

No nuc or organelles 

Cytoplasm constits almost exclusively of packed karatin filaments

7

Stratum Corneum

Consists of 15-20 layers of squamous, karatinized cells

By the end of keratinization, the cells contain only amorphous, fibrillar proteins with plasma membranes surrounded by the lipid rick layer 

These fully karatinized cells or cornified cells called SQUAMES are continuously shed at the epidermal surface as the desmosomes and lipid rick cell envelopes break down

8

Squamous cell carcinoma

Stratum spinosum (keratinocytes)

9

Basal Cell Carcinoma

Stratum Basale (basal cells) 

10

Melanoma

Stratum Basale (melanocytes) 

11

Merkel Cell Carcinoma

Stratum Basale (merkel cells) 

12

Friction Blisters

Fluid buildup between epidermis and dermis 

13

Hypopigmentation (albinism)

Congenital defect in melanin producing pathway.

Tyrosinase defect.

Final products pheomelanins and eumelanins 

14

Eumelanins

Black brown pigment created by melanocyte

15

Pheomelanin

Pigment in red hair 

16

Depigmentation (Vitiligo)

Acquired condition with loss of decreased activity of melanocytes 

17

Dermis 

Connective tissue that supports epidermis 

fibroblasts

macrophages

mast cells 

other leukocutes 

Collagen (I and III) 

Elastic fibers 

 

18

Layers of Dermis 

Papillary layer ( loose connective tissue) 

Reticular layer ( dense irregular connective tissue) 

19

Dermatofibroma

arise from fibroblasts/ dendritic cells?

 

20

Dermatofibrosarcoma Proteburans 

Arises from Fibroblasts 

21

Hemangioma

Arises from endothelial cells (vessels)

22

Hemangiosarcoma

Arises from enothelial cells (Vessels) 

23