week 19 (skin microbial interactions and wound healing) Flashcards
within skin environments, what substance disrupts the balance
antibacterial wash
microbes colonise moist and oliy skin regions around what structure
hair follicles
_____prevents bacterial penetration to the dermis
keratinisation
gland secretions contain defences including slightly acidic sweat and what?
antimicrobial peptides
damaged skin gives opportunities for microbes to invade what layers (3)
hypodermis
subcutaneous fat layer
blood stream
damaged skin gives opportunities for microbes to invade the hypodermis, subcutaneous fat layer and blood stream where they can cause what
serious illness
what characteristics do Langerhans cells possess
motile dendritic cell in epidermis
antigen presenting: phagocytose pathogens and present antigenic surface proteins to T cells
what characteristics to Keratinocytes possess
possess toll like receptors (TLRs)
detect pathogens
release cytokines to induce Langerhans and T cell movement to site of infection
what are characteristics of dermal dendritic cells, macrophages and innate lymphoid cells (ILC )
antigen presenting in dermis
ILCs orchestrate immune responses among T cells and can suppress attack of helpful bacteria
how many phases are there in the skin wound healing response
3
what are the 3 phases in the skin wound healing response
Inflammatory phase
Proliferative Phase
Remodelling Phase (maturation phase)
when does the inflammatory phase occur in the wound healing response
first 48 hours
what occurs in the inflammatory phase within the skin wound healing response
release of inflammatory cytokines
within the inflammatory phase in the skin wound healing response the release of inflammatory cytokines promote what
promotes immune cell chemotaxis (macrophage, T cells) to site of wound
accumulation = pus
what is the cell of origin for EGF
platelets, macrophages
what is the cell of origin for FGF
macrophages, mast cells, T lymphocytes, endothelial cells
what are the cells of origin for IFN (alpha, beta, and gamma)
lymphocytes, fibroblasts
what are the cells of origin for Ils (1, 2, 6, 8)
macrophages, mast cells, keratinocytes, lymphocytes
what are the cells of origin for KGF
fibroblasts
what are the cells of origin for PDGF
platelets, macrophages, endothelial cells
what are the cells of origin for TGF-alpha
macrophages, T lymphocytes, keratinocytes
what are the cells of origin for TGF-beta
platelets, T lymphocytes, macrophages, endothelial cells, keratinocytes
whar are the cells of origin for thromboxane A2
destroyed wound cells
what are the cells of origin for TNF
macrophages, mast cells, T lymphocytes
in the skin wound healing response what is the length of time for the proliferative phase
first 1-2 weeks
in the skin wound healing response, within the proliferative phase, where do growth and division of epithelial cells come from
stratum basale (epithelization)
in the proliferative phase, where does angiogenesis occur
dermis
in the proliferative phase, what occurs in the dermis
angiogenesis
in the proliferative phase where does fibroblast proliferation occur
dermis
in the proliferative phase, fibroblast proliferation in dermis deposits what
collagen
in the proliferative phase, fibroblast proliferation in dermis deposit collagen to create what
supporting matrix over which the epidermal keratinocytes can grow
in the proliferative phase, fibroblasts produce what
dermal granulation tissue
within the skin wound healing response, how long does the remodelling phase last
2 weeks -> months/years
in the remodelling phase, there can be a result of scarring, why?
type III collagen becomes replaced by Type I
in the remodelling phase, cross linking of collagen helps what
increases tensile strength
in the remodelling phase, what increases tensile strength
cross linking of collagen
what are antibiotic peptides produced by
skin epithelial cells
Beta defensins form part of what
innate immune response mechanism
permeabilize bacterial outer wall causes what
lysis
staphylococcus epidermidis is gram _____
positive
staphylococcus epidermidis is ______ and ______ coloniser of what
permanent and ubiquitous colonsier of human skin
staphylococcus epidermidis resists colonisation of
other bacteria
staphylococcus epidermidis has mechanisms for what
host immune evasion
what skin condition causes boils and abscesses
staphylococcus aureus
what skin condition (bacteria) colonises the human skin, lung, and gut
staphylococcus aureus
what does staphylococcus aureus secrete (name as many as possible (7))
coagulase (blood clots)
hyaluronidase (breaks down desmosomes junction between cells)
staphylokinase (degrades fibrin and basement membrane attachments
lipase(degrades protective sebaceous oils)
lactamase (degrades penicillin)
catalase (resists reactive oxygen species attack)
virulence factors (causes rapid colonisation)
staphylococcus aureus infection of the skin (whats the name)
folliculitis
what does quorum sensing mean
homeostatic mechanism involving released peptide signals (autoinducer peptides, AIPS) that keep bacterial population stable
acne is an anearobic bacterium found where
in dermal pores and hair follicles
what is the nutrient source for acne (Propionibacterium acnes)
sebum, shed keratin
elevated sebum secretion is increased by what
induced by sex hormones
follicle blockage provides perfect growth conditions
what is sebum produced by
holocrine secretion
malassezia is found where
common fungal commensal of human skin
malessezia is part of what
normal flora of the epidermis
where is demodex mites found
normal skin fauna found in hair follicles on the cheeks
mites ad rosacea called what
demodex mites
what is rosacea
inflammation and thickening of the skin
