The Skin, Burns, and Wound Healing Flashcards
List the functions of skin
protection, water balance, temperature regulation, immune functions, sensation and metabolism
List the layers of the skin in order from outer to inner
epidermis, dermis, hypodermis
What are the epidermal derivatives?
hair, nails, glands
What parts of body have thick skin and what is a key characteristic?
soles of feet, palms, hairless
What does epidermis primarily consist of?
keratinocytes
What is epidermis classified as?
stratified squamous epithelium
What main function the epidermis provide?
protective physical barrier
List the layers of the epidermis in order from outer to innermost.
Stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale
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Briefly describe some characteristics of the stratum corneum
stratum corneum has no nucleus/organelles to stop disease replication, contains dead keratinocytes, has lipid coated layer to form water barrier
Briefly describe some characteristics of the stratum lucidum
occurs in thick skin only, clear layer, is sub-division of corneum, no nucleus or organelles
Briefly describe some characteristics of the stratum granulosum
contains granules for keratin formation and water resistance
Briefly describe some characteristics of the stratum spinosum
prickly layer, contains daughter cells from basale
Briefly describe some characteristics of the stratum basale
deepest layer, single layer of cells, contains stem cells for regeneration of epidermis
Describe the process of keratinocyte maturation
stem cells divide in the basale and the daughter cells are pushed up superficially this process takes 7-10days, dead keratinized cell are lost from the corneum after 2 weeks
Describe other cells within the epidermis
Langerhans’s cells: immune cells, respond to pathogens and cancer cells
Melanocytes: located in basale, produce melanin and transfer it to keratinocytes to protect DNA from irradiation
Merkel’s cells: located in basale, sensory receptor cells
List the layers of the dermis in order from upper to lower
papillary is the upper layer and reticular lower
What are the functions of the dermis
to support epidermis, sensory awareness of environment with hair follicles and glands
Describe main functions of hypodermis
holds integument to underlying tissue and permits movement of skin
What benefit do stem cells in hair follicles have on skin?
can regenerate epidermis if needed
describe pathway of hair production
starts at hair bulb at base of hair follicle, epithelial cells divide and push upward becoming keratinized = dead cells = hair
Differentiate between the different types of exocrine glands
sebaceous glands: produce sebum, lubricate hair and skin
merocrine sweat glands: produce sweat for temp regulation, found all over body
apocrine sweat glands: found in axilla, nipples, pubic and anal regions, secretion attracts bacteria=odour
describe the two processes possibly involved in wound healing
regeneration: uninjured cells divide and replace injured cells returning to near normal structure and function
scar formation: damaged tissue is replaced by connective tissue, structure restored but function is reduced
List the stages of wound healing
1) inflammatory phase
2) proliferative phase
3) maturation phase
Describe the inflammatory phase of wound healing
occurs immediately after lasting 4-6 days, involves formation of blood clot resulting in temp covering to protect from pathogens, inflammation increases vascular permeability, neutrophil and macrophage levels
Describe the proliferative phase of wound healing
last 1-14 days, involves cell division in order to replace lost tissue, proliferation in dermis involving angiogenesis fibroblasts migration, proliferation and deposition of new collagen to provide temp structure, granulation tissue with extensive capillary bed, high proportion of fibroblasts
Describe the maturation phase of wound healing
lasts 8 days to 1year, granulation tissue replaced by scar tissue, capillaries recede, connective tissue remodelled with stronger collagen fibres, more organised and increased tensile strength
differentiate between first and second intention healing
first: superficial and clean wounds, minimal scar formation
second: large wound with bigger SA, more scarring as more granulation tissue, myofibroblasts contract and pull tissue together
Describe first degree burns
impact epidermis only, superficial
describe second degree burns
superficial partial thickness: impact epidermis and top layer of dermis, very painful as receptors are exposed as blisters break
deep partial thickness: impact epidermis and most of dermis
describe third degree burns
full thickness: impact epidermis, dermis and hypodermis, sometimes muscle
Healing requires intact skin _______ and ______ cells
appendages, dermal
How are third degree burns treated?
skin graft
Describe the different zones in the local response to burn injuries
zone of coagulation: centre zone, irreversible tissue damage, coagulative necrosis
zone of stasis: tissue compromised and ischaemic, outcome variable, can worsen
zone of hyperaemia: dilated blood vessels but no structural change to tissue, will heal
describe burn shock
systemic response involving multiple organ systems with a fluid shift resulting in hypovolemia and decreased cardiac output
What causes fluid shift and hypovolemia after a burn?
increased capillary permeability, plasma volume is reduced and there is evaporative water loss from burn site, plasma shift occurs from blood vessels to interstitial space causing oedema with less fluid in blood throughout body
