Skin, definitions & lesions Flashcards
What is the main type of skin
Keratinocytes
Why type of tissue is skin
Stratified squamous epithelium
Desquamation refers to
Maturation of keratinocytes as they move toward the surface of the skin and ultimately die & shed.
Thick skin in comparison to normal skin
Thicker skin has an additional lucidum layer
2-3 layers of flattened keratinocytes
How many layers are present in the basal layer
1 layer
Pacinian corpuscle
Pressure and high frequency vibrations
Largest if encapsulated nerve endings
Holocrine process is when
The entire cell is shed in the secretory process
Most abundant tissue of the dermis
Collagen 70%
How does the blood supply to dermis change in cold weather?
Arteriovenous anatomoses open and blood flow bypasses the capillary loop-blood is transferred directly from arterioles to venues to conserve heat
Factors affecting drug distribution
Blood flow
Plasma protein binding
Tissue protein binding
Barriers to distribution
Plasma protein binding depends on
Affinity of drug for protein
Concentrations of drug & protein
Number of binding sites on the protein
Free drug + protein =
Drug protein complex (reversible)
Macule
Localised area of clout or textural change in skin. Can be:
- hyoerpigmented
- erythematous as in haemamgioma
Papule
Small solid elevation of skin <5mm
Nodule
Elevation of skin >5mm involving any layer, may be oedematous or solid
Cyst
Nodule consisting of an epithelial lined cavity filled with fluid or semisolid material
Vesicle
Small blister <10mm diameter
Clear fluid accumulated within the epidermis
Dermatitis herpetiformis (sub epidermal)
Intra-epidermal vesicles
Bulla
Large blister > 10mm diameter
May be intra or sub epidermal
Pustule
Visible collection of free pus in vesicles/bulla
May indicate infection
(Unless in psoriasis)
Wheal
Transitory, compressible papule/plaque of dermal oedema, red/white, signifying urticaria
Plaque
Palpable/plaque-like elevation of skin
2cm diameter rarely >5mm height
Scale
Accumulation of thickened, horny layer keratin in the form of readily detachable fragments
Usually indicate inflammatory change & thickening of epidermis
Ulcer
Circumscribed area of skin loss extending through epidermis into dermis (chronic wound)
