Human Physiology Week 3 - Inflammation Study Guide

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Questions and Answers

What is one of the primary roles of leukocytes in inflammation?

Release hormones for temperature regulation

Eliminate injurious stimuli (correct)

Inhibit tissue repair

Promote blood vessel growth

What process allows leukocytes to migrate out of blood vessels into the interstitial space?

Margination

Chemotaxis

Diapedesis (correct)

Stasis

Which of the following best describes margination in the context of inflammation?

Fluid absorption from tissues

Transfusion of platelets

Leukocyte accumulation to blood vessel walls (correct)

Blood vessel constriction

In what way does the lymphatic system contribute to the inflammatory response?

Drains exudate and reduces edema Signup and view all the answers

What is lymphangitis characterized by?

Red streaks under the skin Signup and view all the answers

Which mediator is primarily responsible for increasing vascular permeability during inflammation?

Histamine Signup and view all the answers

What is the result of chemotaxis during inflammation?

Attraction of more leukocytes to the area Signup and view all the answers

What is primarily responsible for the redness and heat observed during inflammation?

Vasodilation and increased blood flow Signup and view all the answers

Which characteristic best differentiates acute inflammation from chronic inflammation?

Infiltration of neutrophils Signup and view all the answers

What condition is most likely to cause chronic inflammation?

Extensive necrosis with no regeneration Signup and view all the answers

Which of the following is a feature of exudate?

High protein content with cellular debris Signup and view all the answers

How does vasodilation contribute to inflammation?

By increasing blood flow to the injured tissues Signup and view all the answers

What does the term 'effusion' refer to in the context of inflammation?

Leakage of exudate or transudate into anatomical space Signup and view all the answers

What is the primary role of increased vascular permeability during inflammation?

To allow plasma proteins and leukocytes to exit the bloodstream Signup and view all the answers

What type of cell accumulation is observed in granulomatous inflammation?

Macrophages and lymphocytes Signup and view all the answers

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.
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.
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

Acute inflammation:
- Infections
- Tissue necrosis
- Foreign bodies
- Immune reactions
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

Goal: To increase the movement of plasma proteins and circulating cells from the intravascular space to the injury site.
- This process is called "exudation."
Increased capillary permeability:
- Widened inter-endothelial spaces allow fluid and protein leakage.
Vasodilation:
- Initially increases blood flow to the area.
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

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.
Process:
- Stasis: Engorgement slows blood flow in the region.
- 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

Lymphatic vessels drain exudate from the interstitium:
- Reduces edema.
- Removes inflammatory stimuli.
- Removes leukocytes.
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.