The Skin, Burns, and Wound Healing

Question 1

List the functions of skin

Answer 1

protection, water balance, temperature regulation, immune functions, sensation and metabolism

Question 2

List the layers of the skin in order from outer to inner

Answer 2

epidermis, dermis, hypodermis

Question 3

What are the epidermal derivatives?

Answer 3

hair, nails, glands

Question 4

What parts of body have thick skin and what is a key characteristic?

Answer 4

soles of feet, palms, hairless

Question 5

What does epidermis primarily consist of?

Answer 5

keratinocytes

Question 6

What is epidermis classified as?

Answer 6

stratified squamous epithelium

Question 7

What main function the epidermis provide?

Answer 7

protective physical barrier

Question 8

List the layers of the epidermis in order from outer to innermost.

Answer 8

Stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale
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Question 9

Briefly describe some characteristics of the stratum corneum

Answer 9

stratum corneum has no nucleus/organelles to stop disease replication, contains dead keratinocytes, has lipid coated layer to form water barrier

Question 10

Briefly describe some characteristics of the stratum lucidum

Answer 10

occurs in thick skin only, clear layer, is sub-division of corneum, no nucleus or organelles

Question 11

Briefly describe some characteristics of the stratum granulosum

Answer 11

contains granules for keratin formation and water resistance

Question 12

Briefly describe some characteristics of the stratum spinosum

Answer 12

prickly layer, contains daughter cells from basale

Question 13

Briefly describe some characteristics of the stratum basale

Answer 13

deepest layer, single layer of cells, contains stem cells for regeneration of epidermis

Question 14

Describe the process of keratinocyte maturation

Answer 14

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

Question 15

Describe other cells within the epidermis

Answer 15

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

Question 16

List the layers of the dermis in order from upper to lower

Answer 16

papillary is the upper layer and reticular lower

Question 17

What are the functions of the dermis

Answer 17

to support epidermis, sensory awareness of environment with hair follicles and glands

Question 18

Describe main functions of hypodermis

Answer 18

holds integument to underlying tissue and permits movement of skin

Question 19

What benefit do stem cells in hair follicles have on skin?

Answer 19

can regenerate epidermis if needed

Question 20

describe pathway of hair production

Answer 20

starts at hair bulb at base of hair follicle, epithelial cells divide and push upward becoming keratinized = dead cells = hair

Question 21

Differentiate between the different types of exocrine glands

Answer 21

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

Question 22

describe the two processes possibly involved in wound healing

Answer 22

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

Question 23

List the stages of wound healing

Answer 23

1) inflammatory phase
2) proliferative phase
3) maturation phase

Question 24

Describe the inflammatory phase of wound healing

Answer 24

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

Question 25

Describe the proliferative phase of wound healing

Answer 25

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

Question 26

Describe the maturation phase of wound healing

Answer 26

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

Question 27

differentiate between first and second intention healing

Answer 27

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

Question 28

Describe first degree burns

Answer 28

impact epidermis only, superficial

Question 29

describe second degree burns

Answer 29

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

Question 30

describe third degree burns

Answer 30

full thickness: impact epidermis, dermis and hypodermis, sometimes muscle

Question 31

Healing requires intact skin _______ and ______ cells

Answer 31

appendages, dermal

Question 32

How are third degree burns treated?

Answer 32

skin graft

Question 33

Describe the different zones in the local response to burn injuries

Answer 33

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

Question 34

describe burn shock

Answer 34

systemic response involving multiple organ systems with a fluid shift resulting in hypovolemia and decreased cardiac output

Question 35

What causes fluid shift and hypovolemia after a burn?

Answer 35

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