54 Questions
What is the main purpose of inflammatory mediators?
To trigger processes in an inflammatory reaction
What is the role of active mediators in response to injurious stimuli?
Produce and release in response to various injurious stimuli
Which type of mediators are differentiated according to their origin into cell-derived and plasma-derived?
Inflammatory Mediators
What is the effect of mediators on inflammatory cells?
They trigger activation and accumulation of inflammatory cells
How are inflammatory mediators characterized once activated?
Short-lived
Which system's proteins can be activated by both microbes and damaged tissues to trigger inflammation?
Immune system proteins
What effect do mediators have on blood vessels during inflammation?
Enhanced blood flow through vasodilation
In addition to increasing vascular permeability, what else do microvascular changes during acute inflammation involve?
Plasma protein leakage and white blood cell leakage
What is a common characteristic of active mediators that distinguishes them from other substances?
Short-lived after activation
Which type of cytokines is produced by monocytes/macrophages?
Monokines
What is the function of Interferons?
Activate macrophages and NK cells
Which cytokines are key in acute inflammation?
Tumor necrosis factors
What is the role of Nitric Oxide in inflammation?
Act as a potent vasodilator
Which type of mediators circulate in an inactive form?
Plasma protein-derived mediators
What do activators do to plasma protein-derived mediators?
Maintain balance by transforming them into an active form
How many types of Interleukins are there?
> 15 types
Which cells are involved in the process of phagocytosis?
Neutrophils and Macrophages
What are the three steps of phagocytosis?
Recognition and attachment, Engulfment, Killing or degradation
In which type of inflammation do Monocytes and Macrophages play a predominant role?
Chronic Inflammation
What is the predominant cell type in Acute Inflammation?
Neutrophils
Which type of immunity is associated with Acute Inflammation?
Innate Immunity
What is the duration of Chronic Inflammation compared to Acute Inflammation?
Weeks to Months to Years
Which type of inflammation is characterized by persisting reactions to tissue injury?
Chronic Inflammation
What is the outcome of Chronic Inflammation compared to Acute Inflammation?
Tissue destruction, fibrosis, necrosis
What is the main difference between Monocytes/Macrophages and Neutrophils in inflammation?
Monocytes/Macrophages are mainly involved in chronic inflammation, while Neutrophils are mainly involved in acute inflammation.
What is the effect of vasoactive amines like histamine in inflammation?
Vasodilatation
Where are vasoactive amines like histamine primarily sourced from in inflammation?
Mast cells, basophils & platelets
Which cell-derived mediator of inflammation is responsible for mediating increased vascular permeability and chemotaxis?
Arachidonic Acid derivatives (Prostaglandins & Leukotrienes)
What is one of the key effects of Platelet-Activating Factors (PAF) in inflammation?
Vasodilation
Which mediator is involved in inducing vasodilatation, pain, and fever during inflammation?
Prostaglandins & Leukotrienes
Where are Arachidonic Acid (AA) Metabolites primarily sourced from in inflammation?
Mast cells & leukocytes
What is the source of Platelet-Activating Factors (PAF) in inflammation?
Mast cells and other leukocytes
What is the role of vasoconstriction in the process of inflammation?
Decrease in blood flow to the affected area
Which cell-derived mediator of inflammation is involved in mediating chemotaxis and leukocyte adhesion?
Platelet-Activating Factor
Which process involves the production of reactive oxygen species (ROS) by phagocytes as a defense mechanism against pathogens?
Nitric Oxide synthesis
What is the role of chemotaxis in acute inflammation?
Recruits leukocytes to the site of injury
Which group of mediators includes interleukins and interferons?
Cell-derived mediators
What is the main function of induced platelet degranulation during inflammation?
Releasing inflammatory mediators
Which signaling molecule acts as a vasodilator and plays a role in neurotransmission, as well as being involved in inflammation?
Nitric Oxide
What is the source of Nitric Oxide (NO) in inflammation?
Endothelial cells & macrophages
Which type of cytokines include Interleukins and Interferons?
Interleukins (IL)
What is the role of Platelet-Activating Factors (PAF) in inflammation?
Trigger platelet degranulation
Which process do neutrophils primarily carry out during inflammation?
Oxidative burst
What is the main function of chemotaxis during inflammation?
Attract leukocytes to the site of injury
What is the main effect of Nitric Oxide in inflammation?
Vasodilatation
Which of the following is NOT an effect of Cytokines in inflammation?
Platelet degranulation
What process is primarily responsible for Induced platelet degranulation in inflammation?
Oxidative burst
Which of the following is a key characteristic of Chemotaxis during inflammation?
Leukocyte adhesion
What major process is associated with the Oxidative burst during inflammation?
Leukocyte adhesion
Which of the following is a key role of Nitric Oxide in inflammation?
Enhancing oxidative burst in phagocytic cells
What is the primary function of Cytokines in inflammation?
Regulating chemotaxis of immune cells
Which process is induced by platelet degranulation during inflammation?
Oxidative burst
What is the main purpose of Chemotaxis during inflammation?
Recruiting neutrophils and macrophages to the site of injury
Which of the following processes is NOT associated with the action of the Oxidative Burst in phagocytic cells?
Promoting platelet aggregation
Study Notes
Phagocytosis
- Phagocytosis is the process of engulfment of solid particulate material (e.g., bacterial, necrotic tissue, or foreign material) by phagocytic cells.
- Types of phagocytic cells: Neutrophils, Macrophages
- Three steps of phagocytosis: 1) Recognition and attachment, 2) Engulfment, 3) Killing or degradation
Inflammation
- Inflammation can be classified into Acute or Chronic inflammation
- Differences between Acute and Chronic Inflammation:
- Acute Inflammation: Immediate reaction of tissue to injury, rapid response (hours to weeks), innate immunity, mainly neutrophils, local and systemic signs, outcome usually mild and self-limiting
- Chronic Inflammation: Persisting reactions of tissue to injury, slow response (weeks/months/years), cell-mediated, monocytes/macrophages and lymphocytes, often severe and progressive, tissue destruction, fibrosis, necrosis
Components and Events of Acute Inflammation
- Acute inflammation has 4 major components:
- Vascular Changes: Alteration in vascular caliber with increased blood flow (vasodilation)
- Microvascular Changes: Alteration in permeability of microvasculature (increased vascular permeability)
- Cellular Events: Emigration, accumulation, and activation of WBCs in the site of injury (cellular recruitment and activation)
- Mediators: Derived from plasma proteins and cells
Mediators
- Mediators are chemical substances that trigger certain processes in an inflammatory reaction
- Mediators are differentiated according to their origin:
- Cell-derived mediators
- Plasma-derived mediators
Cell-Derived Mediators
- Vasoactive amines (Histamine):
- Source: mast cells, basophils, and platelets
- Effects: vasodilation, venular permeability increase, endothelial activation
- Arachidonic Acid derivatives (Prostaglandins and Leukotrienes):
- Source: mast cells and leukocytes (mainly neutrophils)
- Effects: vasodilation, pain, fever, increased vascular permeability, chemotaxis, leukocytes adhesion, and activation
- Platelet-Activating Factors (PAF):
- Source: mast cells and other leukocytes (mainly neutrophils)
- Effects: vasodilation, increased vascular permeability, leukocyte adhesion, oxidative burst, chemotaxis, induced platelet degranulation
- Cytokines:
- Source: produced by activated lymphocytes and macrophages
- Effects: modulate the functions of other cell types, involved in acute and chronic inflammation
- Examples: Lymphokines, Monokines, Interleukins (IL), Interferons (INF), Growth factors, Tumor necrosis factors
- Nitric Oxide (NO):
- Source: soluble gas produced by endothelial cells and macrophages
- Effects: potent vasodilator, regulator of inflammation, actively reducing the effect of other proinflammatory mediators
Plasma-Derived Mediators
- Circulate in an inactive form
- Must be transformed into an active form by an activator
- Numerous, specific, and non-specific
- All activators have natural in-activators to maintain balance
Test your knowledge on cell-derived mediators involved in the inflammatory response, including vasoactive amines, arachidonic acid derivatives, platelet-activating factor, cytokines, and nitric oxide. Learn about the processes like vasoconstriction, altered vascular permeability, activation of inflammatory cells, chemotaxis, cytotoxicity, tissue degradation, pain, and fever.
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