skin, structure and function-related to infections and burns

Question 1

name the structure of the skin from superficial to deep

Answer 1

• Epidermis
  -Dermis (papillary dermis, reticular dermis,epidermal ridges, dermal papillae)
• hypodermis/ subcutaneous tissue

Question 2

name the structure of the epidermis from deep to superficial

Answer 2

• stratum basale
• stratum spinosum
• stratum granulosum
• stratum lucidum
• stratum corneum

Question 3

what are the cutaneous barriers to infection

Answer 3

microbiome, chemical, physical, immune barriers

Question 4

microbiome

Answer 4

normal skin flora
inhibits pathogen colonisation/ proliferation
hydrolyse lipids to form epidermal lipids and maintains PH
regulates keratinocytes and t cell differentiation

Question 5

chemical barrier

Answer 5

maintain acidic ph
antimicrobial peptides
natural moisturizing factors

Question 6

physical barrier

Answer 6

tight and adherens junction
desmosomes
lamellar bodies
keratohyaline granules
stratum corneum cornified cell evelope

Question 7

immune barrier

Answer 7

consists of sentinel cells( langerhans, mast, macrophages, dendritic, keratinocytes cells)
sentinel cell surface receptors recognise antigens
release of alarms
local and other recruited cell co-oridnate adaptive immune response

Question 8

classify skin infection into deep and superficial

Answer 8

superfcial: impetigo, erysipelas, folliculitis
deep: cellulitis, fasciitis, furuncle, carbuncle

Question 9

name and explain the pathophysiology of burns

Answer 9

Zone of coagulation = area of insult with immediate cell
death and coagulation of cellular proteins; irreversible
damage
* Zone of stasis = damage less severe but microcirculation
damaged therefore stasis occurs; initially the area appears
viable but may become necrotic in the days after the injury
* Zone of hyperaemia = area of vasodilation due to
inflammation – in burn >20%- 25% body area, inflammation
and neural stimulation can cause the zone of hyperaemia to
extend to the entire body producing a systemic response

Question 10

classify depth of burn

Answer 10

epidermal/ 1st degree
partial thickness 2nd degree: -superficial, superficial dermis
- deep/ deep dermal
full thickness (3rd or 4th degree)

Question 11

epidermal first degree

Answer 11

Epidermal/ first degree
* Epidermal injury: stratum basale intact
* Erythema, painful, dry skin, no blisters, capillary refill present
* Heal spontaneously without sc

Question 12

second degree

Answer 12

Superficial/ Superficial dermal & Mid-dermal
* Epidermis and papillary dermis + reticular dermis
* Blisters, erythema, painful, capillary refill present/ sluggish
- when blisters removed dermis is pink/ white
* Heal spontaneously with/ without dermal scars
- skin adnexal structures are NB
Deep/ Deep dermal
* Epidermis to reticular dermis
* Blisters, blotchy red, no capillary refill, sensation may
be lost
* Do not heal spontaneously, scar

Question 13

3rd or 4th degree

Answer 13

Extend to subcutaneous tissue/
muscle/ bone
* White/ black (eschar), waxy appearance
no capillary refill or sensation
* Do not heal spontaneously, scar

Question 14

State the processes taking place within each skin stratum from deep to superficial (stratum basale to stratum corneum)

Answer 14

• Stratum basale: The only stratum seeing mitotic division of keratinocytes. This is to increase the number of keratinocyes as they are continously pushed up the stratums.
• Stratum spinosum:
  The keratinocytes in this stratum synthesise epidermal lipids and store them within the lamella bodies.
• Stratum granulosum:
  Has keratohyline granules which facilitate the process of keratinization, which is the transformation of keratinocytes into corneocytes (dead skin cells) which will be forming the stratum corneum. Also, must be noted that as these keratinocytes migrate all the way up the stratas they produce protein keratin, contributing to their thinning.
  -This stratum has tight junctions and desmosomes as well.
• Stratum lucidum (N/A)
• Stratum corneum:
  Has a cornified cell envelope (for mechanical strength, resilience)- which was formed through continuous secretion of keratin and through the process of keratinization in stratum granulosum.