Lecture 3- Chronic Inflammation Flashcards
Local Effects of Inflammation
redness (rubor) swelling (tumor) Heat (caldor) Pain (dolor) loss of function
Systemic effects of inflammation
Pyrexia/fever
increased Leukocytes (leukocytosis)
Acute Phase Proteins
Endocrine Changes
How are inflammatory reactions potentially harmful?
If not controlled these can have a huge pathological effect. They underlie important diseases such as rheumatoid arthritis, athersclerosis and hypersensitivity (allergic reactions)
Chronic inflammation is?
When the inflammation cause is prolonged. other leukocytes enter tissues.
When do monocytes become macrophages
When they enter the injured tissue
Neutophils vs macrophages
Both enter via diapaedesis. Neutrophils first. By 24hours the dominant cell type is macrophages which have greater phagocytic/killing potential then neutrophils. Macrophages will ‘hang around’ for as long as needed.
Why is granuloma formation particular to chronic inflammation
A focus of CI with a core of necrosis. THere are microscopic aggregations of macrophages that are transformed into epithelium like cells, a collar of lymphocytes surrounds these
Why do macrophages aggregate
To do the job better, and better remove dead cells and inflammatory exudate.
REPAIR
Mess is converted into viable stable tissue. Happens when the mess generated by injury and subsequent inflammation is too much/ ECM is really damaged.
When does ORGANISATION happen
during repair. Macrophages secrete growth factors (eg FGF), which encourage ingrowth of fibroblasts (to lay down CF) and endothelial cells (to form new vessels)
GRANULATION TISSUE
when the tissue contains many active fibroblasts and new blood vessels.
What happens to granulation tissue
remodelled by regression of vessels and reorganisation of collagen fibres into a FIBROUS SCAR, this generation of fibrous tissue is sometimes referred to as FIBROSIS.
Why do we NOT want fibrous scars?
They represent a loss of pre existing functional tissue, and they may also hinder the remaining functional tissue.
REGENERATION
replacing the parenchymal cells (functional cells) within the tissue that were destroyed. Involves the proliferation of stem cells derived from within the tissue and bone marrow. Commonly seen where there is normally a high cell turnover rate.
Two extremes on the range of eventual outcomes?
1) a fibrous scar (tissue function lost)
2) complete resolution (original structure/function recovered)
