Chapter 06: Innate Immunity: Inflammation and Wound Healing

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Questions and Answers

What type of healing occurs when there is minimal tissue loss?

Healing through repair

Healing by secondary intention

Healing by primary intention (correct)

Healing through regeneration

What is the primary outcome of the repair process in healing?

Prevention of infection

Restoration of original tissue structure

Formation of scar tissue (correct)

Complete regeneration of all tissue

Which phase follows the reconstructive phase in wound healing?

Healing phase

Inflammatory phase

Maturation phase (correct)

Reparative phase

What is a common factor that can lead to dysfunctional wound healing?

Chronic illness Signup and view all the answers

What condition is described as a disruption where the wound pulls apart at the suture line?

Dehiscence Signup and view all the answers

What causes a contracture of scar tissue?

Excessive shortening of collagen Signup and view all the answers

Which factor is NOT typically associated with impaired wound healing in older adults?

Excessive nutrient intake Signup and view all the answers

What are newborns particularly at risk for due to age-related factors?

Impaired neutrophil chemotaxis Signup and view all the answers

Which factor contributes to ischemia related to dysfunctional wound healing?

Poor circulation Signup and view all the answers

In the healing process, what does the maturation phase primarily involve?

Remodeling of the healed wound Signup and view all the answers

What is the primary function of physical barriers in the innate immune system?

To prevent damage and invasion by pathogens Signup and view all the answers

Which of the following is NOT a hallmark of inflammation?

Weight gain Signup and view all the answers

Which system is primarily responsible for stopping bleeding during the inflammatory response?

Clotting system Signup and view all the answers

What are the main products of the complement system involved in the immune response?

C3a, C3b, and C5a Signup and view all the answers

Which factors contribute to the microscopic hallmarks of inflammation?

Vasodilation and accumulation of fluid and cells Signup and view all the answers

Bradykinin in the kinin system is primarily responsible for which of the following effects?

Causing vascular permeability and pain Signup and view all the answers

The primary role of antibacterial peptides like defensins is to:

Act as a biochemical barrier against pathogens Signup and view all the answers

What initiates the inflammatory response in vascularized tissue?

Cellular injury from any cause Signup and view all the answers

Which of the following is NOT part of the three main lines of defence in the human immune system?

T-cell immune response Signup and view all the answers

What is the function of the complement system in the innate immune response?

To recruit phagocytes and destroy pathogens Signup and view all the answers

What is the role of chemokines in the inflammatory process?

They induce chemotaxis of specific cells to the site of inflammation. Signup and view all the answers

Which interleukins are primarily associated with the proinflammatory response?

Interleukin-1 and Interleukin-6 Signup and view all the answers

How do mast cells contribute to the inflammatory response?

By releasing biochemical mediators from granules. Signup and view all the answers

What is the primary function of macrophages in the inflammatory response?

To promote wound healing and clear debris. Signup and view all the answers

Which statement best describes the process of phagocytosis?

It includes multiple steps leading to the destruction of pathogens. Signup and view all the answers

What role do endothelial cells play during inflammation?

They regulate blood flow and allow leukocytes to exit the vessels. Signup and view all the answers

What characterizes chronic inflammation compared to acute inflammation?

It can last more than 2 weeks and often includes granuloma formation. Signup and view all the answers

What is the main function of opsonins in the immune response?

To enhance the effectiveness of phagocytosis. Signup and view all the answers

What is the significance of interleukins in inflammation?

They regulate the activation and differentiation of leukocytes. Signup and view all the answers

During which phase of inflammation do neutrophils primarily function?

Early inflammatory response Signup and view all the answers

Study Notes

Human Defence Mechanisms

Three lines of human defence against injury and infection: innate immunity, inflammatory response, and adaptive (acquired) immunity.
Physical barriers such as skin and mucous membranes serve as the first line of defence against pathogens.
Antibacterial peptides (cathelicidins, defensins, collectins, mannose-binding lectin) act as biochemical barriers in secretions like saliva, tears, and mucus.
Commensal microorganisms on skin and mucous membranes protect against pathogens by chemical release and aiding digestion.

Inflammatory Response

The inflammatory response is the second line of defence, a rapid and nonspecific reaction to cellular injury, limited to vascularized tissues.
Macroscopic signs include redness, swelling, heat, pain, and loss of function.
Microscopic signs involve vasodilation, increased capillary permeability, and cell fluid accumulation at the site of inflammation.
Three plasma protein systems mediate inflammation: complement system, clotting system, and kinin system.

Complement System

Activated by antigen-antibody reactions or bacterial polysaccharides; produces fragments that recruit phagocytes and destroy pathogens.
Key products include C3b (opsonin), C3a, and C5a (both anaphylatoxins).

Clotting and Kinin Systems

Clotting system helps stop bleeding and provides a scaffold for tissue repair.
Bradykinin, an important kinin product, increases vascular permeability, smooth muscle contraction, and induces pain.

Regulation of Inflammation

Inflammation is controlled through inactivating enzymes (carboxypeptidase, histaminase, C1 esterase inhibitor) and the fibrinolytic system.
Various cells like mast cells, endothelial cells, platelets, and phagocytes (neutrophils, macrophages) play roles in inflammation.

Immune Cell Function

Cells in the innate immune system release cytokines that activate other immune responses.
Phagocytic cells, including neutrophils and macrophages, recognize pathogens through pattern recognition receptors (PAMPs and DAMPs).
Cytokines such as chemokines and interleukins promote cell movement and inflammation regulation.

Phagocytosis Process

Phagocytosis involves recognition, engulfment, phagosome formation, fusion with lysosomes, and destruction of pathogens.
Opsonins enhance phagocytosis by binding to pathogens, making them easier targets.

Acute and Chronic Inflammation

Acute inflammation is self-limiting, resolving within 8 to 10 days, characterized by local signs like redness, heat, swelling, and pain.
Chronic inflammation may continue beyond two weeks, marked by lymphocyte and macrophage infiltration, potentially leading to granuloma formation.

Wound Healing

Resolution refers to restoring tissue, while repair involves scar formation.
Healing by primary intention occurs with minimal tissue loss. Secondary intention healing involves extensive tissue damage, resulting in scarring.
Healing phases: reconstructive (beginning of healing) and maturation (remodelling of the healed wound).
Dysfunctional healing may result from factors like ischemia, infection, diabetes, and tobacco use.

Newborns exhibit depressed inflammatory function, affecting neutrophil chemotaxis and complement activity.
Older adults face impaired wound healing due to chronic illnesses, increasing susceptibility to complications.

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Description

Explore the key concepts of innate immunity, inflammation, and wound healing as presented in Chapter 06 of Huether's Understanding Pathophysiology. This quiz will test your understanding of human defense mechanisms, including the roles of physical barriers and inflammatory responses in combating injury and infection.