Outcomes of Acute Infection Flashcards
Possibilities After Acute Inflammation
Resolution
Healing by Repair/Scarring/Fibrosis
Chronic Inflammation
Abcess formation
What happens in Post Inflammatory Resolution
Restitution of normal tissue structure and function
It is rare and may occur when treated very quickly; can occur with pneumonia
Also occurs with non-severe damage
Frequent in epidermal damage as the cells frequently turnover
Labile, Stable, Permanent Regeneration
These terms refer to to the capacity of stem cells to divide and replace specialised cells required
Labile - Replicate through life (e.g. skin and gut)
Stable - Non-dividing normally but capable of regeneration (e.g. liver and kidney)
Permanent - Non-dividing cells (e.g. Brain and Heart)
Scarring in Labile, Stable and Permanently regenerating tissue
Labile – Can Resolve
Stable – Can Resolve or Scar
Permanent – Always scarring
Post Inflammatory Resolution v Repair in terms of:
Which tissues involved
What happens to damaged tissue/stimulus
Presence of Granulation/Scar Tissue
Remodeling and Return to Function
Resolution -
Damage to parenchyma in labile/sterile tissue
Remove damaging stimulus, inflammatory cells, mediators & exudate
Replace injured cells by regeneration
Restore normal function
Minimal/absent evidence of damage
Repair -
Damage to parenchyma and stroma (or brain/muscle)
Replace damaged tissue with connective tissue
Formation of scar & granulation tissue
Lacks functional capabilities of damaged tissue
Summary of Fibrosis
Granulation Tissue - Macrophages, Fibroblasts & Angiogenesis
Fibrosis & Scar Formation - Fibroblasts lay down matrix; Scar formed as amount of collagen laid down is increased to strengthen tissue
Remodelling - Slowly, number of vessels reduce and pale scar remains
Wound Healing Phase of Fibrosis
Inflammatory Phase - Arrival of Macrophages to produce growth factors for next phase
Proliferative Phase
Granulation Tissue builds
Fibroblasts secrete matrix and growth factors for angiogenesis
Epithelial cells regrow over wound
Remodelling Phase
Remodelling/Organisation of Matrix to develop appropriate tissue architecture for its function
Fibroblasts lay down collagen, creating scar
Decreased Vascularity
Pathological fibrosis of Liver and Lungs; Explain why organs are vulnerable
Liver: Cirrhosis
Lung: Interstitial Fibrosis (e.g. asbestosis)
Liver is vulnerable as they barely have connective tissue and are very soft
Fibrosis inhibits normal relationship between blood vessels and cells as inhibited by collagen
Lung is vulnerable as soft alveoli is replaced by hard scar tissue that cannot expand as easily
Growth Factors
Hormone-like molecules that stimulate proliferation, differentiation and maturation of cells
They attract endothelial cells & fibroblasts, forming a role in angiogenesis and production of matrix
Suffix -osis
Pathology involving fibrosis
Abscess Formation
Focal collection of pus (neutrophils, dead cells and fluid)
Arises as result of infection or excessive neutrophil infiltration
Core surrounded by neutrophils & fibroblasts attempting repair, which can become walled off and need draining
Healing by scarring
Chronic Inflammation
Prolonged duration of inflammation
Consequence of persistent infection that is not eliminated during acute inflammation; most viruses, prolonged toxin exposure, immune-mediated inflammation/autoimmune disease
Heals by scarring
What is a genus of bacterium seen in chronic inflammation
Mycobacteria
Cells involved in chronic inflammation
*Macrophages* Lymphocytes Plasma Cells Eosinophils Mast Cells
