Lecture: Pathology 3: How the body responds to injury Flashcards
What are the signs of inflammation?
Heat, pain, redness, swelling, and loss of function.
What is inflammation?
A complex biological response of body tissues to harmful stimuli which involves immune cells, blood vessels and molecular mediators.
What is the function of inflammation?
Function is to eliminate the initial cause of injury, clear out damaged tissues and initiate tissue repair.
What are the characteristics of acute inflammation?
- Short duration but usually severe
- Classically neutrophil granulocytes/polymorphs, antibodies, complement
- May cause mild/self-limited tissue damage or can be severe
What is the purpose of vasodilation in acute inflammation?
Vascular dilation (vasodilation) results in stasis of blood and an increase in hydrostatic pressure beyond normal levels leading to oedema.
What is the purpose of increased vascular permeability and extravasation of fluid in acute inflammation?
Cells, proteins, mediators leak which cause increase in tissue osmotic pressure and lead to more oedema.
What is the purpose of emigration of leukocytes in acute inflammation?
Trigger more immune cells to migrate to are of inflammation to support inflammation and immune clearance of pathogen.
What are the 3 steps of leukocyte emigration in acute inflammation?
- Margination and rolling along the vessel wall
- Adhesion to the activated endothelium
- Emigration through the vessel wall into the surrounding tissues.
What cytokines mediate marginalisation and rolling along the vessel wall?
Mediated by selectins which may be upregulated by Tumour necrosis factor (TNF) and Interleukin 1 (IL-1).
What cytokines mediate adhesion to the activated endothelium?
Mediated by integrins (VCAM-1, ICAM-1) which are also upregulated by TNF and IL-1.
What cytokines mediate emigration of leukocytes through the vessel wall into the surrounding tissues?
Mediated by CD31/PECAM-1
What are the 3 possible outcomes of acute inflammation?
- Complete resolution
- Healing by scarring
- Progression to chronic inflammation
What are the characteristics of chronic inflammation?
- Long duration, varies from mild to severe
- Classically lymphocytes, histiocytes/monocytes, eosinophils, and plasma cells
- May cause severe progressive tissue damage
What is a granuloma?
A granuloma is a collection of activated epithelioid macrophages which is fairly characteristic of chronic inflammation.
What are the 5 Rs of inflammatory response?
- Recognition (of the injurous agent)
- Recruitment (of leukocytes)
- Removal (of the injurous agent)
- Regulation (of the inflammatory response)
- Resolution (or repair)
