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Questions and Answers
What is one of the primary roles of leukocytes in inflammation?
What process allows leukocytes to migrate out of blood vessels into the interstitial space?
Which of the following best describes margination in the context of inflammation?
In what way does the lymphatic system contribute to the inflammatory response?
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What is lymphangitis characterized by?
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Which mediator is primarily responsible for increasing vascular permeability during inflammation?
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What is the result of chemotaxis during inflammation?
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What is primarily responsible for the redness and heat observed during inflammation?
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Which characteristic best differentiates acute inflammation from chronic inflammation?
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What condition is most likely to cause chronic inflammation?
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Which of the following is a feature of exudate?
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How does vasodilation contribute to inflammation?
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What does the term 'effusion' refer to in the context of inflammation?
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What is the primary role of increased vascular permeability during inflammation?
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What type of cell accumulation is observed in granulomatous inflammation?
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Study Notes
Inflammation Signs
- Erythema (redness): Caused by vasodilation and increased blood flow.
- Heat: Also caused by vasodilation and increased blood flow.
- Edema (swelling): Caused by increased vascular permeability and hydrostatic pressure, leading to fluid leakage into interstitial spaces.
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Pain: Can be caused by:
- Direct trauma
- Edema causing pressure
- Swelling of nerve endings
- Chemical mediators
Acute vs. Chronic Inflammation
- Acute inflammation: Characterized by edema (with fluid and plasma proteins) and neutrophil migration.
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Chronic inflammation: Includes lymphocyte, plasma cell, and macrophage infiltration.
- These cells are attracted by chemotaxis from other cells.
- They promote the growth of endothelial cells and fibroblasts.
- This leads to granulation tissue formation.
- It also involves angiogenesis/neovascularization, fibrosis, and tissue destruction.
Causes of Inflammation
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Acute inflammation:
- Infections
- Tissue necrosis
- Foreign bodies
- Immune reactions
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Chronic inflammation:
- Extensive necrosis
- Areas where tissue regeneration is impossible (e.g., heart, CNS, PNS)
- Persistent injurious agent (the underlying cause isn't addressed)
- Repeated episodes of acute inflammation
Granulomatous Inflammation
- A collection of macrophages and lymphocytes.
Exudate, Transudate, and Effusion
- Exudate: High protein fluid with high cellular content. Increased vascular permeability contributes to its formation.
- Transudate: Low protein fluid with minimal cellular content. Starling's forces (filtration) cause its accumulation. There is no increase in vascular permeability.
- Effusion: Leakage of exudate or transudate into anatomical or potential spaces.
Vascular Alterations in Inflammation
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Goal: To increase the movement of plasma proteins and circulating cells from the intravascular space to the injury site.
- This process is called "exudation."
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Increased capillary permeability:
- Widened inter-endothelial spaces allow fluid and protein leakage.
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Vasodilation:
- Initially increases blood flow to the area.
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Decreased blood flow to the area:
- Occurs after fluid leaks out, due to increased blood viscosity.
- Clotting of fluid: Increased fibrinogen levels contribute to clotting.
- Leukocyte migration and accumulation: To destroy pathogens.
Leukocyte Role in Inflammation
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Role:
- Remove and eliminate the injurious stimulus.
- Release toxic substances to kill, inactivate, and degrade pathogens.
- Clean up the area through phagocytosis.
- Release growth factors for healing/regeneration.
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Process:
- Stasis: Engorgement slows blood flow in the region.
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Margination: Leukocytes accumulate along the endothelial cells of blood vessel walls.
- This is facilitated by adhesion molecules that bind leukocytes to each other and to capillaries/venules.
- Diapedesis: Leukocytes exit the blood vessel by squeezing between endothelial cells to reach the interstitial space.
- Chemotaxis: Chemotactic agents (chemokines) attract other cells to the area.
Lymphatic System Role
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Lymphatic vessels drain exudate from the interstitium:
- Reduces edema.
- Removes inflammatory stimuli.
- Removes leukocytes.
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Phagocytes present antigens to B and T cells in lymph nodes:
- This triggers lymphocyte proliferation.
- Lymphadenopathy (enlarged lymph nodes) may occur.
- Leads to further adaptive immune response as necessary.
Lymphangitis
- Inflammation of the lymphatic vessels.
- Characterized by red streaks under the skin which are painful to palpation.
Inflammatory Mediators
-
Histamine:
- Synthesized and stored in mast cells, basophils, and platelets.
- ** Effects:**
- Endothelial contraction
- Increased vascular permeability (exudation)
- Vasodilation
- Bronchoconstriction
- Inactivated by histamine methyltransferase.
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Description
This quiz covers the signs, types, and causes of inflammation. You will learn the differences between acute and chronic inflammation and the biological processes involved. Test your knowledge on erythema, edema, and the role of various immune cells in inflammation.
