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1st lecture of wound
WSU Kirsten Fields
Question | Answer |
---|---|
Largest external organ of the body | skin |
how much does skin weigh | 6lbs |
how long is skin | 20ft |
how much of the body's blood volume does skin receive | 1/3 |
how many dead skins cells do you lose every minute of every day | 30,000 to 40,000 |
how many skins cells are produced at any given time | >300 million |
how many lbs of skin cells are produced in a year | 10lbs |
5 primary fxns of skin | 1. protection 2. temperature regulation 3. sensation 4. metabolism 5. communication |
what does skin protect the body from? | bacterial invasion and external elements (water, chemicals, mechanica, bacterial, viral, UV radiation) |
What does skin prevent excessive loss of? | fluid and electrolytes |
Skin strives to maintain what and has what type of response? | homeostasis and immunological response |
what does skin produce | sebum: a lipid rich oily substance (helps keep flora out) |
where is sebum secreted at | sebaceous glands |
what does sebum provide and what does it do the growth of micro-organisms | provides acidic coating retards it |
what does melanin do and what provides it | protects against UV rays skin pigmentation |
what is the pH of the acid mantle and what does it do? | 5.5 help keep skin from bacteria and fungal infection, indirect protection against microorganisms and alkaline substances helps maintain normal skin flora(staph aureus, staph epidermis, yeast) |
What things would change the pH of skin: | eczema contact dermatitis atopic dermatitis and dry skin diabetes, chronic renal failure and cerebrovascular disease |
what areas are most sensitive to touch | most number of nn endings (fingers, lips, nipples) |
Finger allow for identification without what | sight (stereognosis) |
what type of area would have reduced tactile sensitivity | shaved areas |
hairless reagions - tactile corpuscles- meissner's corpuscles transmit what? | firm tough, hugs, etc via skin to the brain ( how much force u apply to lift something up) |
somatic pain -out body surface- is submitted through what: -superficial acute pain travel at what spd through waht fiber? - deep chronic pain | skin fast : A delta nn fiber slowly : thin myelinated C fibers |
how do you regulate temp | fluid & electrolyte balance (sweat) thermoregulation: (hypothalamus response to internal core temp) peripheral temp receptors assist w/ homeostasis (remove hand if something is hot)-water loss through lungs, skin, buccal mucosa) |
skin temp is regulated by what | vaso dilation and restriction |
metabolism regulation of vit d | synthesis in skin in presence of sunlight-through conversion of sebum sterol to cholecalcifoerol (vit D) |
what are the psychosocial/ communication effects of skin | appearance and care of skin: confidence use of skin in conjunction w/ underlying mm for expression sensation fo touch= feel in of comfort, concern, friendship, love, etc |
what are the two layers of skin | epidermis and the dermis |
how often does the epidermis regenerate | every 4-6 wks |
what does the epidermis do | repels water, protective barrier against micro-organism, prevents water loss, protects against shear, friction and toxic irritants, |
is the epidermis vascular | no its avascular |
what does the epidermis contain | melanin |
what happens to the dead cells of the epidermis | shed |
how many layer of start are there and what are they composed of | 5 keratinocytes |
epithelial cell layers | stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum germinativum |
what is the - superficial layer of dead skin cells. Shed daily, outermost layer (made of keratinocyte cells) | stratum corneum |
what is the -clear layer) only present in thick skin, Cell nothing more than a bag of keratin-found only in palms/soles. | stratum lucidum |
what is the multilayer 1-5 cells thick, cells become depressed and aid n keratin formation-keratinocytes/langerhans cells (where they are). | Stratum granulosum |
what is (spiny layer) several layers thick, cells begin to produce keratin, cells begin to flatten-keratinocytes/langerhans cells | stratum spinosum |
what is (granular layer) AKA stratum basale, only one cell thick. Only layer in which cells undergo mitosis to form new cells. | stratum germinativum |
Protrusions of this layer (rete pegs) extend down into the dermis to provide support and facilitation of fluid and cell exchange between the skin layers.-melanocytes and Merkel cells | stratum germinativum |
-manufacture keratin (protein responsible for the toughness of the epidermis) | keratinocytes |
It takes these cells 4-6 weeks to migrate from the stratum germinativum to the stratum corneum | keratinocytes |
specialized structures which bind adjacent keratinocytes to one another and give cohesion to each layer during its upward progression. | desmosomes |
produce and distribute melanin throughout all the layers of the epidermis | melanocytes |
- first line of defense against environmental antigens | langerhans cells |
- forms the junction between the dermis and the epidermis – this layer keeps the epidermis and dermis from sliding on each other. | basement layer |
As we age, this junction flattens out and diminished the amount of surface between the layers, reducing nutrient transfer, and decreasing resistance to sheering that separates the two layers . | baseemtn layer |
cells of the epidermis | Kertinocytes desmosome melanocytes Langerhans cells basement membran |
supports and nourishes the epidermis | dermis |
varies in thickness depending on area of body | dermis |
contains fewer cells than epidermis - made up of fibroblasts (secretes proteins of collagen and elastin), fibrous and amorphous extracellular matrix (ECM) macrophages, lyphocytes and mast cells | dermis |
has bloods supply | dermis |
has nerves | dermis |
sweat and sebaceous glands are located where and they transported to the body surface through what | dermis sweat ducts |
hair follicles are located where | dermis |
waht is the dermis made up of | protein (collagen and elastin) |
where are the cells for the dermis produced | in bone marrow |
what is the thickest layer of skin | dermis |
(on test)scavenger cells that ingest dead tissues and cells, repair injured tissues, act as defense mechanisms | macrophages |
mast cells |