Healing Flashcards
1
Q
Name the stages of wound healing
A
- Haemostais
- Inflammation
- Proliferation
- Remodelling
- May progress at different rates
- can overlap
- may have different stages occurring in different areas of same lesion
2
Q
Describe Haemostasis
A
- Occurs immediately after the injury (unless clotting disorder)
- Vasospasm at time of injury, rapidly subsides- leads to relaxation and further bleeding
- Platelets activated by exposed collagen from damaged vessels
- promote vasoconstriction
- initiate formation of platelet plug
- start vessel healing
3
Q
Describe acute inflammation
A
- fully established by 24 hours after injury
- can last up to 96 hours if disrupted
- cardinal signs observed:
- redness
- swelling
- heat
- pain
- loss of function - Neutrophils and macrophages remove cell debris
- establish microenvirobment for proliferation (granulation) phase
- essential for healing
4
Q
Descrive proliferation
A
-can last 3-4 weeks or longer
- generation of new:
- Endothelium = angiogenesis
- Epithelium= epithelialisation
- Connective tissue stroma = fibroplasia/ desmoplasia
5
Q
Describe remodelling
A
- Maturation and contraction phase of wound healing
- begins 3-4 weeks after injury (only if earlier stages complete)
- can last 2 years +
- removal of damaged connective tissue
- replacement with new connective tissue
6
Q
Causes of impaired wound healing?
A
- Spontaneous causes
- foreign bodies
- infections
- neoplasia - Wound specific variables
- body site
- vascular supple/ oxygenation
- mechanical stress
- desiccation - Systemic variables
- nutrition
- age
- sex
- immobility
- diseases - Exogenous variables
- medication (cytotoxic drugs, NSAIDs, glucocorticoids)
- radiation
- environment
7
Q
Synthesis of ECM?
A
-Fibroblasts- produce collagen and proteoglycans
8
Q
Describe fibrosis
A
- fibroblasts align along planes of tissue stress during development
- Langer’s lines (tension lines)
- Surgical incisions along Langer’s lines reduce postsurgical scar formation
-Feline fibroblasts: responsive to injury (associated with neoplastic transformation)
- fibroblasts and endothelial cells migrate into wounds
- growth factors released during inflammation promote proliferation of fibroblasts and endothelial cells
- produce EM
- provisional connective tissue is remodelled into mature matrix
9
Q
What is Granulation tissue?
A
= distinctive arrangement of connective tissue fibres, fibroblasts and blood vessels
- fibres and fibroblasts running parallel to wound surface
- new vessels running perpendicular to wound surface
10
Q
Appearance of granulation tissue?
A
- red and granular appearance
- new vessels are leaky and bleed easily
11
Q
Excessive granulation tissue=
A
proud flesh (hypertrophic scar)
12
Q
Wound contraction?
A
- Microfibroblasts
- specialised fibroblasts with contractile activity
- form in wounds in response to tissue stress
- contracts the wound to bring edges together
13
Q
Describe Angiogenesis
A
- Proteolysis of ECM
- Migration and chemotaxis
- Proliferation
- Lumen formation, maturation, and inhibition of growth
- Increased permeability through gaps and trancytosis
14
Q
what does VEGF do?
A
-makes new blood vessels
15
Q
Will it regenerate, repair or scar?
A
- depends on cell type (is it post mitotic?)
- depends on extend of injury- is the basement membrane intact?
- where tissue dies = scar
- if you lose basement membrane = scar
