Inflammation Flashcards
What are the causes, consequences, and purpose of inflammation?
Inflammation is a normal protective response of the body to tissue injury caused by harmful stimuli. It is not a disease itself but usually a manifestation of a disease. The purpose of inflammation is to eliminate the initial cause of cell injury, remove necrotic cells and tissue, and initiate the process of repair. It can be both beneficial and harmful.
What are the various components of inflammation?
Vascular events: Alterations in vascular calibre resulting in blood accumulation (vasodilation) and structural changes that permit plasma proteins to leave circulation (increased vascular permeability).
Cellular events: Emigration of neutrophils/leukocytes from microcirculation and accumulation in the focus of injury (cellular recruitment and activation).
How do acute and chronic inflammation differ?
Acute inflammation: First and often temporary tissue responses to injury, relatively short duration (few minutes to few days), includes leakage of protein-rich fluid from blood vessels and recruitment of neutrophils/leukocytes.
Chronic inflammation: Often prolonged tissue reactions after the initial response to injury, longer durations (days to years), includes influx of lymphocytes, plasma cells, and macrophages.
What are the common causes of inflammation?
Common causes include microbial infections (bacteria, viruses like TB, HIV), hypersensitivity reactions (allergy), physical agents (trauma, radiation, heat, cold), chemicals (corrosives, acids, alkalis), and tissue necrosis (ischaemic infarction).
What is the cascade of events in acute inflammation?
1.Vasodilation of small blood vessels adjacent to the injury.
2.Increased blood flow to the injured area.
3.Endothelial cells swell/contract to increase vascular permeability.
4.Exudation of fluid leading to oedema.
5.Chemotaxins attract neutrophils to the site of injury.
6.Migration of neutrophils/leukocytes through stages: margination, rolling, adhesion, and emigration.
7.Neutrophils/leukocytes recognize foreign particles and begin phagocytosis.
What are the vascular and cellular events that occur during inflammation?
Vascular events: Vasodilation, increased blood flow to the injured area, endothelial cells swell/contract to increase vascular permeability, leading to fluid loss from vascular space into interstitial space (oedema).
Cellular events: Emigration of neutrophils/leukocytes from microcirculation, accumulation in the focus of injury, recognition of foreign particles, and phagocytosis.
What are the signs of inflammation?
Redness: Dilatation of small blood vessels in the affected area.
Heat: Increased blood flow to the affected area.
Swelling: Fluid accumulation in the extravascular space (oedema).
Pain: Stretching of tissues due to oedema and chemical mediators (bradykinin, prostaglandins).
Loss of function.
What are the benefits of inflammation? A: The benefits of inflammation include:
Dilution of toxins: Carried away in lymphatics.
Entry of antibodies: Due to increased vascular permeability into the extravascular space.
Transport of drugs: Antibiotics to the site where bacteria are multiplying.
Fibrin formation: Stops movement of microorganisms, trapping them.
Delivery of nutrients and oxygen: Essential for cells such as neutrophils.
Stimulation of immune response: Drainage of fluid exudate into lymphatics.
What are the possible outcomes of acute inflammation? A: The outcomes of acute inflammation include:
Resolution: Total repair and removal of the insult.
Fibrosis and scar formation: Occurs in cases of significant inflammation.
Chronic inflammation: Results from a persisting insult or immune-mediated response.
Formation of an abscess.
How do vascular and cellular events overlap during inflammation?
Both vascular and cellular events overlap during inflammation. Vascular events like vasodilation and increased vascular permeability lead to fluid leakage into the interstitial space, which facilitates the migration and accumulation of neutrophils/leukocytes at the site of injury, where they perform phagocytosis and other immune responses.
What are the harmful effects of inflammation? A: The harmful effects of inflammation include:
Digestion of normal tissues: Enzymes like collagenases and proteases may digest normal tissues.
Swelling of acutely inflamed tissues: May obstruct airways, for example.
Inappropriate inflammatory response: Allergies can cause further inappropriate inflammation (chronic).
What are the substances that initiate and regulate inflammation in the body?
1.Cell-derived: Includes histamine, heparin, leukotrienes, prostaglandins, platelet-activating factor (PAF), nerve growth factor, and some interleukins.
2.Plasma protein-derived: Includes mediators in fluid exudate that influence cells and blood vessels, such as components of the complement system.
What are the roles of mast cells and platelets in inflammation?
Mast cells: Have membrane receptors (IgE, complement components C3a and C5a) and release histamine, heparin, leukotrienes, prostaglandins, PAF, nerve growth factor, and some interleukins.
Platelets: Involved in coagulation and thrombotic phenomena, generate thromboxane A₂ and PAF, and release platelet-derived growth factor for healing.
What are eicosanoids and their function in inflammation?
Eicosanoids are locally acting bioactive signaling lipids that regulate a diverse set of homeostatic and inflammatory processes linked to numerous diseases.
What are the characteristics of chronic inflammation?
Predominance of lymphocytes, plasma cells, and macrophages.
Formation of granular and scar tissue.
Can be primary or result from unresolved acute inflammation.
Examples include chronic ulcers, chronic abscesses, thickening of hollow viscus walls, and granulomatous inflammation.
