Acute Inflammation Quiz

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Questions and Answers

What is a primary purpose of acute inflammation?

To increase tissue necrosis

To enhance metabolic activity in the body

To induce chronic inflammatory responses

To eliminate or limit the spread of injurious agents (correct)

Which of the following is NOT a characteristic of acute inflammation?

Margination of neutrophils

Short duration of symptoms

Extended fibrosis (correct)

Accumulation of fluid exudate

Which chemical mediators are primarily involved in controlling acute inflammation?

Chemical mediators from plasma or cells (correct)

Neurotransmitters

Hormones from the endocrine system

Nutritional factors

What is the initial response of living tissues to injury called?

Acute inflammation Signup and view all the answers

Which type of infection is commonly associated with acute inflammation?

Microbial infections, including pyogenic organisms Signup and view all the answers

Which of the following is a potential complication of acute inflammation?

Systemic effects and local complications Signup and view all the answers

What happens to neutrophils during the acute inflammatory response?

They migrate towards the site of injury Signup and view all the answers

Which type of acute inflammation is associated with hypersensitivity reactions?

Allergic inflammation Signup and view all the answers

Which adhesion molecule is primarily expressed on endothelial cells?

E-selectin Signup and view all the answers

What process allows leukocytes to migrate through the vessel wall?

Diapedesis Signup and view all the answers

Which of the following substances can act as a chemotactic factor for leukocytes?

Bacterial products Signup and view all the answers

What is the primary role of neutrophils during inflammation?

Phagocytosing microorganisms Signup and view all the answers

How does vasodilation contribute to the inflammatory response?

It increases blood flow to the affected area Signup and view all the answers

What is NOT a purpose of the exudation of fluid during acute inflammation?

Reduces immune response Signup and view all the answers

Which of the following changes is characteristic of acute inflammation?

Neutrophil margination and migration Signup and view all the answers

What effect does pain and loss of function have during acute inflammation?

Promotes rest and prevents further damage Signup and view all the answers

Which clinical sign is associated with redness during acute inflammation?

RUBOR Signup and view all the answers

What happens to arterioles at the onset of acute inflammation?

Transient vasoconstriction Signup and view all the answers

What is the result of increased vascular permeability during acute inflammation?

Exudation of protein-rich fluid Signup and view all the answers

How does Starling's Law relate to fluid movement in acute inflammation?

Balances hydrostatic and osmotic pressures Signup and view all the answers

What type of fluid loss occurs during inflammation, exudate or transudate?

Exudate with high protein content Signup and view all the answers

What effect does vasodilatation have in the context of acute inflammation?

Increases heat and redness of the area Signup and view all the answers

What characterizes stasis during acute inflammation?

Concentration of red blood cells in small vessels Signup and view all the answers

Which of the following components is NOT a characteristic microscopic feature of acute inflammation?

Fibrosis Signup and view all the answers

What is the primary characteristic of transudate?

Low protein content with specific gravity less than 1.012 Signup and view all the answers

Which mechanism is NOT associated with increased vascular permeability during acute inflammatory responses?

Decreased vascular pressure Signup and view all the answers

During neutrophil recruitment, which step follows the rolling of neutrophils along the endothelium?

Adhesion Signup and view all the answers

What is a purulent exudate primarily characterized by?

Presence of neutrophils and cell debris Signup and view all the answers

What leads to margination of leukocytes during inflammation?

Stasis in blood flow Signup and view all the answers

What occurs during the process of emigration of neutrophils?

They migrate through the blood vessel wall Signup and view all the answers

Which factor is not related to the mechanisms that increase vascular permeability?

Formation of intercellular junctions Signup and view all the answers

Which event occurs last in the sequence of leukocyte recruitment to the site of injury?

Migration towards the chemotactic stimulus Signup and view all the answers

Study Notes

Acute Inflammation - Overview

Acute inflammation is the body's local response to injury caused by any agent.
It's a protective mechanism to eliminate or limit the spread of injurious agents, and remove necrosed cells and tissues.
Acute inflammation is innate, immediate, and early, typically lasting minutes to hours or a few days.
Key objectives include understanding the causes and purposes of acute inflammation, its macroscopic and microscopic features (edema, vasodilation, neutrophil margination/migration), and the relationship between microscopic and macroscopic changes.

References

Robbins basic pathology
Muir's Textbook of pathology

Objectives

Major causes and biological purposes of acute inflammation
Macroscopic features of acute inflammation
Microscopic features of acute inflammation, including edema and vasodilation
Neutrophil margination and migration
Relationship between microscopic and macroscopic changes

Causes of Acute Inflammation

Microbial infections (bacterial, viral, fungal, parasitic) are common causes
Hypersensitivity reactions (acute phase) against environmental substances or "self" tissues
Physical and chemical agents (burns, frostbite, radiation, toxins) causing host cell injury
Tissue necrosis (ischemia, physical/chemical injury)

Clinical Features of Acute Inflammation

Main clinical signs include:
- RUBOR (redness)
- TUMOR (swelling)
- CALOR (heat)
- DOLOR (pain)
- Loss of function

Acute Inflammation - Major Characteristics

Vascular Reaction: Accumulation of fluid exudate and neutrophils in tissues
Controlled by chemical mediators derived from plasma or cells
It's a protective mechanism but can lead to local and systemic complications, usually followed by repair.

Vascular Changes

Transient vasoconstriction of arterioles (few seconds)
Vasodilation of arterioles and capillaries, leading to increased blood flow (heat and redness)
Increased permeability of blood vessels, causing exudation of protein-rich fluid into tissues, and slowing of circulation.
Concentration of red blood cells (RBCs) in small vessels, increasing blood viscosity (stasis)

Increased Vascular Permeability

Increased vascular permeability leads to movement of protein-rich fluid and blood cells into the extravascular tissues.
This causes increased osmotic pressure of interstitial fluid and more fluid outflow from the blood into the tissues.

Starling's Law and Fluid Loss

Fluid flow across vessel walls depends on the balance of hydrostatic pressure within the vessels and the difference in colloid osmotic pressure between plasma and interstitial fluid.
Increased hydrostatic pressure leads to increased fluid flow out of the vessels.
Increased colloid osmotic pressure of the interstitial fluid pulls fluid into the vessels, and/or prevents fluid from leaving.

Exudate vs. Transudate

Exudate: High protein content, specific gravity above 1.02, characteristic of inflammation
Transudate: Low protein content, specific gravity less than 1.012, caused by hydrostatic pressure imbalance (e.g., venous obstruction)

Edema

Edema is excess fluid in the interstitium, and can be transudate or exudate.
Edema leads to increased lymphatic drainage.
Pus is a purulent exudate, rich in neutrophils and cell debris.

Lymphatic Drainage in Inflammation

Lymph flow increases during inflammation to drain edema fluid, leukocytes, and cell debris from extravascular space
In severe inflammatory reactions, especially to microbes, lymphatics may transport the offending agent, contributing to dissemination.

Mechanisms of Increased Vascular Permeability

Endothelial cell contraction (intercellular gaps in postcapillary venules)
Endothelial injury (e.g., burns, infections)
Increased transcytosis (proteins through intracellular vesicles)
Leakage from new blood vessels (angiogenesis)

Cellular Events in Acute Inflammation (Leukocyte Recruitment)

Stasis slows blood flow, leading to margination of neutrophils at vessel walls.
Neutrophils roll along endothelium (rolling).
Neutrophils adhere firmly to endothelium (adhesion).
Neutrophils migrate through the vessel wall (emigration).
Neutrophils migrate in interstitial tissues toward a chemotactic stimulus (chemotaxis).

Chemotaxis & Phagocytosis

Leukocytes move towards sites of infection/injury along a chemical gradient (chemotaxis).
Exogenous and endogenous substances are chemotactic, including bacterial products, cytokines, complement system components, and products of the lipoxygenase pathway.

Phagocytosis

Neutrophils phagocytose microorganisms.
Activated neutrophils release toxic metabolites/enzymes harming host tissue.

How Do These Changes Combat Injury?

Exudation of Fluid: Delivers plasma proteins (immunoglobulins, inflammatory mediators, fibrinogen) to the injured area, diluting toxins. Increases lymphatic drainage, delivering microbes/antigens to phagocytes and the immune system.
Infiltration of Cells: Removes pathogenic organisms/necrotic debris.
Vasodilation: Increases blood flow/delivery to the injured area (increases temperature).
Pain and Loss of Function: Enforces rest, reduces further trauma.

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Description

Test your knowledge on the fundamentals of acute inflammation. This quiz covers the characteristics, chemical mediators, and physiological responses involved in this critical aspect of the immune response. Explore the initial reactions and complications associated with acute inflammation.