click below
click below
Normal Size Small Size show me how
A&P of skin and soft
WOCN program
Term | Definition |
---|---|
Epidermis characteristics | Outermost layer of skin, avascular, turnover time usually 28 days |
Layers of epidermis | Stratum corneum, lucidum, granulosum, spinosum, basale (aka germinativum) |
Stratum Corneum structures | Dead keratinocytes, thin, stacked, anucleated, cells filled with keratin, stratum has lipid matrix, originate in the basal layer, have fully differentiated, shed daily |
Stratum corneum function | Protection against aqueous, chemical, physical assault Thickness varies with age, gender and disease |
Keratin | Tough fibrous insoluble protein that is primary component of skin, hair and nails |
Stratum lucidum structure | 1-5 cells thick, has lysosomal enzymes, only found in thick skin areas- palms and soles of feet, is translucent |
Stratum lucidum function | Degrades nucleus and organelles of keratinocytes |
Stratum granulosum structure | flattened cells, contain keratohyalin granules, Odland bodies |
Stratum granulosum function | has Odland bodies that produce lipids and enzymes, the mortar of the epidermis, provides barrier to water loss |
Stratum spinosum structure | has keratinocytes, Langerhans cells |
Stratum spinosum function | Provide adhesion between cells, provides resistance against mechanical forces, synthesize keratin filaments |
Stratum basale structure | Aka germinativum, inner most layer, basal layer, next to basement membrane, active cells,, has rete's pegs, melanocytes, epidermal stem cells |
Stratum basale function | is reproductive layer, proliferating keratinocytes, anchors the epidermis via Retes pegs cells start here and migrate upwards |
Basement membrane zone structure | 2 zones- lamina lucida and lamina densa , has hemidesmosomes for adhesion fibronectin is the major protein |
Basement membrane zone function | Anchors the epidermis to the dermis- this is the layer that is affected blister formation, full thickness wounds and third degree burns in wound healing the BMZ is disrupted and must be reformed |
Dermis structure | 2 layers, papillary and reticular fibroblasts present, is vascular and innervated is 2-4mm thick ground substance present, contains collagen and elastin, glands and hair follicles |
Dermis function | protection, connective tissue |
Papillary dermis structure | just below Retes ridges, has pappliae that connect with Retes, capillary loops that supply O2 and nutrients via BMZ, lymph vessels present |
Papillary dermis function | Supply O2 and nutrients to stratum basale |
Reticular dermis structure | contains sebaceous glands, hair follicles, sweat glands,contains most of the connective tissue , has fibroblasts, mast cells, and macrophages |
Reticular dermis function | supports the skin, has connective tissue and blood vessels gives skin it's strength and elasticity |
Dermal proteins | Collagen and elastin |
Collagen | Fibrous protein with high tensile strength |
Elastin | Coiled fibers that allow for skin to return to shape |
Hypodermis structure | Subcutaneous fat, |
Hypodermis function | Attaches dermis to underlying structures, insulates, distributes pressure |
Skin functions | barrier/protection, Vit D synthesis, thermoregulation, sensation, insulation, immunity |
protective functions | Protection against pathogens, UVR, fluid loss, environmental irritants |
Thermoregulation | Barrier between outside and internal environment to maintain body temp, circulation and sweating are mechanisms |
explain Sensation | Nerve receptors perceive - pain, touch, temp, itch and pressure - also a protective mechanism - burning itching and tickling are basic sensations |
Vit D synthesis | UVR converts a sterol to cholecalciferol, then is converted to calcitrol |
Skin immune system | Langerhans cells, tissue macrophages, mast cells, AMPs (antimicrobial peptides) |
Langerhans cells | Antigen presenting cells present to T cells |
explain Tissue macrophages | Bacteriocidal, tumoricidal, antigen presenters, secrete growth factors, cytokines, atherogenisis, coagulation, wound healing and remodeling |
Mast cells | Usually in reticular dermis, release histamines, chemotactic agents - involved in allergic responses, inflammatory diseases |
acid mantle | inhibits pathogenic growth, 4-6.5 |
Merkel cells | Sense light touch- are in rete pegs, near hair follicles, , are mechanreceptors- |
Meissner corpuscles | Touch reception |
Pacinian corpuscles | Pressure, coarse touch vibration and tension |
What separates the 2 major layers of the skin | Basement membrane zone |
How long does it take a cell to go from stratum basale to corneum | 14 - 28 days |
Retes pegs | Epidermal protrusions of the basal layer that point downward into the dermis |
Melanocytes | Approx. the same # in all skin types, in basal layer, melanin is in the dendritic process as melanosomes |
Factors that alter skin characteristics | Age, hydration, sun, soaps, nutrition, medications, disease |
How do Meds effect skin characteristics | Can alter skin flora, alter inflammatory response, cause dermatitis slow wound healing can cause photosensitivity photo toxicity . |
skin ph ranges from ___ to ___ with a mean of ____ | 4,6.8, 5.5 |