DD-Dermatology and the Epidermis Flashcards
the structure and functions of the skin
Skin is the largest organ
Fitzpatrick Skin Types
1- Never tans, always burns 2- Tans with difficulty, usually burns 3- Average tanning, sometimes burns 4- Easily tans, rarely burns 5- Very easy to tan, very rarely burns 6- Never burns
Top 5 Skin Diseases
Eczema Acne Bacterial skin diseases Viral Urticaria
melanocyte pigment cells which produce melanin packaged in granules called_________to protect from UV light
melanosomes
black to brown pigment
Eumelanin
yellow to red-brown pigment
Pheomelanin
melanosomes smaller and distributed in clusters above the nucleus in the keratinocyte
Light Skin
melanosomes larger and distributed individually throughout the cytoplasm of the keratinocyte
Dark Skin
1- Never tans, always burns 2- Tans with difficulty, usually burns 3- Average tanning, sometimes burns 4- Easily tans, rarely burns 5- Very easy to tan, very rarely burns 6- Never burns
Fitzpatrick Skin Types
DUE TO TYPE OF MELANIN PRODUCED, AS WELL AS SIZE AND DISTRIBUTION OF MELANOSOMES
Skin Pigmentation
ABSENCE OF MELANOCYTES
Vitiligo
- Decoration/Beauty
- Barrier
- Vitamin D synthesis
- Water Homeostasis
- Thermoregulation
- Insulation/Calorie Reservoir
- Touch/Sensation
Functions of the Skin
Dark Skin
melanosomes larger and distributed individually throughout the cytoplasm of the keratinocyte
Light Skin
melanosomes smaller and distributed in clusters above the nucleus in the keratinocyte
Autoimmune destruction of melanocytes
Acquired depigmentation
Commonly seen in periorificial and acral locations
Microscopic finding is a complete absence of melanocytes
Vitiligo
ABSENCE OF MELANOCYTES
-Water Homeostasis
-Thermoregulation
example?
Sweat
Vitamine D can come from?
Diet
UVB/skin
Epidermis
the outer layer of cells covering an organism
Base of Epidermis
Melanocytes
Langerhans Cell
APC of Epidermis
Innermost layer of the epidermis
Contains small round cells called basal cells
Location of Stem Cells
BASAL CELL LAYER
Attachment point of basal cells to the basal lamina of the dermal epidermal junction
Hemidesmosomes
predominant cell type in the epidermis, the outermost layer of the skin, constituting 90% of the cells found there.
KERATINOCYTES
acute or chronic autoimmune skin disease, involving the formation of blisters
Bullous Pemphigoid
AB to Hemidesmosomes
Appears spiny due to the fact that the cells are held together with spiny projections.
The thickest layer of the epidermis, just above the basal layer
Stratum SpinosumSPINY CELL LAYER
______ produce keratin, a tough protective protein that makes up the majority of the structure of skin, hair and nails.
Keratinocytes
FORM SKIN BARRIER
Desmosomes
attachment between Keratinocytes
Pathology: INTRAepidermal blisters
Pemphigus Vulgaris
Cells in this layer start to loose their nuclei
Prominent keratohyalin granules contain filaggrin which cross links keratin in the formation of the cornified cell envelop
Stratum Granulosum
GRANULAR CELL LAYER
Made up of dead and desquamating keratinocytes
Breakdown of filaggrin forms Natural moisturizing factor which binds H2O to keep skin moist
Stratum Corneum
CORNEOCYTE CELL LAYER
__________ is a filament-associated protein that binds to keratin fibers in epithelial cells
Filaggrin
w/o this, weak barrier. dry skin
Small cells associated with nerve endings in epidermis.
seem to be involved in neural development and tactile sensation.
Merkel cells
is only present in thick skin where it helps reduce friction and shear forces between the stratum corneum and stratum granulosum.
Stratum Lucidum
CLEAR CELL LAYER
Flat lesion
macule- small
patch- large
Raised Smooth lesion
papule
plaque
cyst
nodule
Raised Scaly lesion
papule with scale/plaque with scale
Fluid Filled lesion
vesicle/bulla/pustule
Redness lesion
erythema
erythroderma
telangiectasia
Purpura lesion
ecchymoses
petechiae
palpable purpura
Discrete, solid, elevated body
Less than 1.0 cm in diameter
May be further classified by surface change
Scale, Crust
Papule
Solid, flat-topped, elevated area of skin
Greater than 1.0 cm and broader than thick
May be further classified by surface change
Plaque
Firm and well-defined lesion
May be dermal or subcutaneous
Greater than 1.0 cm
Nodule
Surface Changes
Crust
Scale
Fluid filled cavity or elevation
Form within or just below epidermis
Less than 1.0 cm in diameter
Vesicle
Fluid filled “blister”
Greater than 1.0 cm in diameter
Bulla
Circumscribed elevation that contains pus
Less than 1.0 cm in diameter
Color usually whitish-yellow
Pustule
Localized, blanchable redness
Caused by increased blood flow
Erythema
Generalized, blanchable redness
Caused by increased blood flow
May be associated with desquamation or extensive scaling
Erythroderma
Visible, persistent, dilation of small, superficial cutaneous blood vessels
Telangiectasias
Flat discoloration of skin or mucous membranes
Due to extravasation of blood
Color transitions over time and ranges from blue-black, brown-yellow, or green
Ecchymoses (Bruise)
Tiny 1-2mm (pinpoint spots)
Resulting from tiny hemorrhages
Color is red or violaceous
Petechiae
Raised and palpable discoloration
Due to vascular inflammation and extravasation of red blood cells (vasculitis)
Color is red or violaceous
Palpable Purpura
A thinning of epidermal, dermal or subcutaneous tissue
Atrophy
superficial or dermal
Localized loss of epidermal or mucosal epithelium
Causes can include injury or denuding of vesicle or bulla roof (removal)
Erosion
Circumscribed loss of epidermis and at least upper dermis
Ulcer
A deep linear crack or cleavage
Found in areas of thickened skin
Fissure
“Scab”
Adherent, thick, dry crust
Causes can include trauma, infection or excoriating skin disease
Color is black
Eschar (Crust)
Regions where opposing skin surfaces come in contact that may cause friction- Skin Folds
Extensive Distribution: Intertriginous
Pertaining to the skin surface overlaying muscles that flex joints, such as biceps
Flexural
