Inflammation Flashcards
Inflammation is a complex reaction of what type of tissue?
Vascularised connective tissue
Give 2 pros of inflammation
without inflammation:
1- wounds and injured organs would never heal
2-infections would go unchecked
Give 3 cons of inflammation
inflammation can be dangerous because:
1- life threatening hypersensitivity reactions
2- chronic inflammatory diseases; rheumatoid arthritis
3- repair by fibrosis may lead to problems; disfiguring scars
What are the 2 types of inflammation?
Acute - initial rapid and often short-lived series of tissue reactions to injury
Chronic - the subsequent and often prolonged tissue reactions following the initial response
What are the 5 principal causes of acute inflammation?
1- infections 2-hypersensitivity reactions 3-physical agents (trauma) 4-irritant and corrosive chemicals 5- foreign bodies
What are the 5 physical characteristics of inflammation?
1- Rubor 2-Calor 3-Tumor 4-Dolor 5-loss of function
What are the phases of acute inflammation?
1- vascular phase –> i)vasodilation, ii) increased permeability of blood vessels
2- exudative and cellular phase –> i) fluid exudate, ii) cellular component
Explain and describe the vascular phase of acute inflammation
i) vasodilation = results in increased blood flow, thus rubor and calor
ii) increased vascular permeability= brought about by chemical mediators histamine and bradykinin, forms gaps in venules, leakage of fluid confined to POST-CAPILLARY VENULES.
Explain and describe the exudative and cellular phase of acute inflammation
i) the fluid exudate = contains fibrin, proteins and white blood cells. fluid exudate escapes from the permeable venules, and is continually removed by lymphatics then replaced. Net increase in extravascular fluid is called ODEMEA.
ii) the cellular component = diagnostic feature of acute inflammation is neutrophil accumulation in the extracellular space.
What are neutrophils?
Neutrophils are white blood cells (leukocytes) which move from the blood stream and into a wound to engulf and digest contaminants.
What are the 6 functions of neutrophils?
1- kill microorganisms 2-ingest offending agents 3-degrade necrotic tissue 4-produce chemical mediators 5-produce toxic oxygen radicals 6-produce tissue damaging enzymes
What is the first step in order for neutrophils to reach the site of inflammatory stimulus?
MARGINATION = loss of plasma and increased plasma viscosity slows down blood flow and allows neutrophils (white blood cells which usually flow in the lumen of the blood vessel) to flow in the plasmatic zone [ONLY OCCURS IN VENULES]
What is the second step in order for neutrophils to reach the site of inflammatory stimulus?
ADHESION = neutrophils adhere to endothelial cell wall (interaction between adhesion molecules on neutrophil surface and the endothelial wall)
What is the third step in order for neutrophils to reach the site of inflammatory stimulus?
TRANSENDOTHELIAL MIGRATION = after successful adhesion to endothelium, neutrophils insert pseudopodia (arm-like projections of cytoplasm) into the junctions between endothelial cells. Then cross through basement membrane into extravascular space.
What is this 3 step process of neutrophil migration to the site of inflammatory stimulus termed as?
Chemotaxis
Give the 4 compounds which direct neutrophils in chemotaxis (chemotactic compounds)
1- bacterial products
2- complement components
3- cytokines
4- products produced by neutrophils themselves
What happen once the neutrophil has reached the wound debris, it must attach to the micro-organism (debris), but what process must happen first?
OPONISATION -
a particle is first “coated” in OPSONINS (antibodies which attach to antigens on particle) in order to be better targeted in phagocytosis.
What is phagocytosis?
Phagocytosis is the complex process by which phagocytes such as neutrophils and macrophages engulf and ingest micro-organisms or other cells and foreign particles
What is the first step of phagocytosis?
RECOGNITION AND ATTACHMENT = typical but not absolute requirement - leucocyte surface receptors recognise particles.
What is the second step of phagocytosis?
ENGULFMENT = cytoplasmic extensions flow around the particle and completely engulf particle - phagosome
Phagosome membrane fuses with lysosomal (vesicles in cytoplasm) membrane to create phagolysosome - discharge lysosomal content (digestive enzymes) into phagolysosome