Skin DSAs Flashcards
Skin Function- Major Types
Protective covering – Non-permeable barrier to protect internal systems from external environment.
Water, chemicals, toxic substances, “dirt”, etc.
UV Radiation
Tactile interaction with external world Touch Pain Pressure Temperature
Body temperature regulation
Vascular dilatation/constriction superficial and deep dermal plexuses
Sweating
Structural for heat retention (adipose tissue; hair, particularly scalp)
Skin FunctionsNot commonly mentioned, but Important
Sexual attractiveness
Skin Appearance important part of sexual attractiveness
Immune system – production of cytokines and defensins
– antigen presentation via Langerhans Epidermal Dendritic Cells and possibly dermal dendrocytes
Langerhans cells
are dendritic cells located in upper spinous layer
ThreeBasic Layers of Organization
Epidermis Dermis - papillary dermis - reticular dermis Subcutis (Hypodermis)
Adnexae:
Three major adnexal structural units and specialized sensory nerve structures
Pilar (hair) units: pilosebaceous units, arrector pili muscles
Eccrine units: eccrine glands and ducts
Apocrine units: apocrine glands and ducts
layers of epidermis
stratum corneum lucidum graulosum spinosum basale
dermal-epidermal junction
- pappillary dermis
- reticular dermis
Come, Let’s Get Sunburned
Apocrine Glands location
deep dermis and often at junction of reticular dermis and subcutaneous tissue (axilla, scalp, perineum, etc.)
melanocytes
produce pigment that are is absorbed by the squamous cells
squamous cell connection
intercellular bridges = desmosomes
allows for the dx of squamous cell carcinoma
Papillary Dermis
Finely woven Type I collagen, parallel to surface
- some Type III and network of elastic fiber
- healing by secondary intention
- capillaries ofsuperficial plexus (blushing, sunburn)
Basement Membrane interface with epidermis
- defines invasion of carcinoma
* contains proteins involved in blistering immune disease
*** bullous pemphigoid, dermatitis herpetiformis, epidermolysis bullosa
- other inflammatory conditions
discoid lupus erythematosus (thickens BM)
location of the superficial vascular plexus
papillary dermis
skin sensation-
Lamellar/Lamellated/Pacinian corpuscle
Meissner/tactile corpuscles/papillae
General Skin Nerve supply
Lamellar/Lamellated/Pacinian corpuscle
encapsulated nerve ending
pressure receptor
found in deep dermis or hypodermis
Meissner/tactile corpuscles/papillae
touch receptor
confined to dermal papillae
most numerous on hands and feet
General Skin Nerve supply
free nerve endings detect pain and temperature
innervation by sympathetic nervous system controls blood flow and hair movement
Subcutis - Hypodermis: structure
Loose and dense subcutaneous connective tissue - Adipocytes arranged in lobules; Fibroconnective tissue arranged in septae Lobular Panniculitis (e.g. pancreatitis) Septal Panniculitis (e.g. erythema nodosum)
- Large number of blood vessels – deep vascular plexus which sends perpendicular small arteries to traverse the reticular dermis and supply arterial blood to the superficial vascular plexus in the dermal papillae of the papillary dermis
Vasculitis is a pathologic state
Connects reticular dermis with fascia of underlying tissue (muscle, bone, tendon)
Subcutis- Hypodermis: purpose
Body temperature regulation:
- Both vascular regulation and insulation by adipose tissue.
Primary depot for fat storage
- large energy reserve along with the omentum
Major skin layer where aging is most evident
- With aging there is progressive loss of the adipose component of subcutaneous tissue, particularly in extremities (hands and feet) leading to “gaunt look”
Erosion
Superficial partial thickness loss of the epidermis
Excoriation
Traumatic abrasion of the skin, often from scratching
Ulceration
Full thickness loss of the epidermis revealing dermis or subcutis
Fissure
Linear ulceration
Exocytosis
Inflammatory cells within the epidermis
Lichenification
Thickened and rough skin; may be the result of repeated rubbing (lichen simplex chronicus/prurigo nodularis)
Scale
Dry, horny, platelike excrescence; usually the result of imperfect cornification
Macule
<5 mm in diameter discolored flat lesion
Patch
> 5 mm in diameter discolored flat lesion
Papule
< 5 mm elevated somewhat dome-shaped lesion
Nodule
> 5 mm elevated or non-elevated rounded mass
Plaque
Elevated flat-topped lesion, usually > 5 mm across
Wheal
Itchy elevated lesion with variable blanching and erythema from edema
Blister
Any clear fluid-filled raised lesion
Vesicle
<5 mm blister
Bulla
> 5 mm blister
Pustule
Elevated area filled with pus, may resemble a blister
Onycholysis
Separation of nail from the nail bed
Hydropic swelling (balooning)
Intracellular edema of cells
Spongiosis
Intercellular edema of the epidermis
(= excema)
Acantholysis
Loss of intercellular attachment of keratinocytes
Vacuolization
Formation of vacuoles within or adjacent to cells
Acanthosis
Thickened stratum spinosum
Hyperkeratosis
Thickened of the stratum corneum
Hypergranulosis
Hyperplasia of stratum granulosum
Parakeratosis
Keratinization with retained nuclei in the stratum corneum
Dyskeratosis
Premature keratinization of cells below the stratum granulosum
Lentiginous
Single unit proliferation of melanocytes along basal layer
Papillomatosis
Finger-like hyperplasia and enlargement of dermal papillae
Verrucous
Looking like a verruca vulgaris (wart), also used grossly
Aging Changes in Skin
INTRINSIC AGING: WRINKLES
- aberrant basal layer proliferation: risk of neoplasm
- decrease in melanocytes: UV damage, “whitening“
- decrease in Langerhans cells
- thinning: decrease in ground substance, cells and adnexae, stiffer collagen and elastic fibers
Decreased hair shaft diameter; by age 70 lose 25 - 50% of cross-sectional diameter present in young people
Decreased # hair follicles; Decreased oil production -“Dry Skin” = xerosis***
Changes in distribution/prominence of hair:
Solar Elastosis
Telangiectasia - dilated small blood vessels
Actinic (basophilic) degeneration of reticular dermis collagen
Sunburn
Acute injury caused by mid-UV radiation
Changes in the dermis
- Increased blood flow
- Superficial blood vessels show endothelial swelling, perivenular edema, mixed perivascular inflammatory infiltrate
