Chapter 7 Flashcards, Innate Immunity Inflammation and Wound Healing
What are the three layers of human defense?
The three layers of human defense are barriers, innate immunity (including the inflammatory response), and adaptive (acquired) immunity.
What constitutes the first line of defense in human defense mechanisms?
The first line of defense includes physical, mechanical, and biochemical barriers as well as the normal microbiome.
What are examples of physical and mechanical barriers?
Examples include the skin and mucous membranes.
What role do antibacterial peptides play in defense?
Antibacterial peptides in mucous secretions, perspiration, saliva, tears, and other secretions provide a biochemical barrier against pathogenic microorganisms.
How does normal bacterial flora protect the body?
Normal bacterial flora protects by releasing chemicals that prevent colonization by pathogens.
What is inflammation?
Inflammation is a rapid and nonspecific protective response to cellular injury from any cause, occurring only in vascularized tissue.
What are the macroscopic hallmarks of inflammation?
The macroscopic hallmarks of inflammation are redness, swelling, heat, pain, and loss of function of the inflamed tissues.
What is the microscopic hallmark of inflammation?
The microscopic hallmark of inflammation is an accumulation of fluid and cells at the inflammatory site.
What are the three key plasma protein systems that mediate inflammation?
The three key plasma protein systems are the complement system, the clotting system, and the kinin system.
How can the complement system be activated?
The complement system can be activated by antigen-antibody reactions (classical pathway) or by bacterial polysaccharides (lectin pathway or alternative pathway).
What are the most biologically potent products of the complement system?
The most biologically potent products are C3b (opsonin), C3a (anaphylatoxin), and C5a (anaphylatoxin, chemotactic factor).
What is the function of the clotting system?
The clotting system stops bleeding, localizes microorganisms, and provides a meshwork for repair and healing.
What is the role of bradykinin in inflammation?
Bradykinin causes vascular permeability, smooth muscle contraction, and pain.
What types of cells are involved in the inflammatory process?
Cells involved include mast cells, endothelial cells, platelets, phagocytes (neutrophils, eosinophils, monocytes, macrophages, dendritic cells), natural killer (NK) cells, and lymphocytes.
What are pattern recognition receptors (PRRs)?
PRRs are expressed by most cells and recognize molecules produced by infectious microorganisms (PAMPs) or products of cellular damage (DAMPs).
What are cytokines and their role in inflammation?
Cytokines are biochemical mediators secreted by innate immune cells that activate other cells; important cytokines include interleukins, chemokines, and interferons.
What are the most important proinflammatory cytokines?
The most important proinflammatory cytokines are IL-1, IL-6, and tumor necrosis factor-alpha (TNF-α).
What is the function of interferons?
Interferons are produced by virus-infected cells and stimulate neighboring healthy cells to produce substances that prevent viral infection.
What do chemokines do?
Chemokines induce leukocyte chemotaxis.
What initiates the inflammatory response?
The mast cell is the most important activator of the inflammatory response, releasing biochemical mediators from granules and synthesizing other mediators.
What is the role of histamine in inflammation?
Histamine causes dilation of capillaries and retraction of endothelial cells, increasing vascular permeability.
How do endothelial cells regulate inflammation?
Endothelial cells regulate circulating components of the inflammatory system and maintain normal blood flow by preventing spontaneous activation of platelets and the clotting system.
What happens to endothelial cells during inflammation?
During inflammation, endothelial cells express receptors that help leukocytes leave the vessel and allow fluid to pass into tissues.
What is the role of platelets in inflammation?
Platelets interact with the coagulation cascade to stop bleeding and release mediators that promote and control inflammation.
What is the function of polymorphonuclear neutrophils (PMNs)?
PMNs are the predominant phagocytic cells in the early inflammatory response, exiting circulation by diapedesis and moving to the inflammatory site by chemotaxis.
What is the role of eosinophils in inflammation?
Eosinophils release products that control the inflammatory response and are the principal cells that kill parasitic organisms.
What is the function of macrophages in inflammation?
Macrophages are the predominant phagocytic cells in the late inflammatory response, highly phagocytic, responsive to cytokines, and promote wound healing.
How do dendritic cells connect the immune systems?
Dendritic cells collect antigens at the site of inflammation and transport them to lymph nodes where immunocompetent B and T cells reside.
What is phagocytosis?
Phagocytosis is a multistep process for eliminating pathogens and foreign debris, including recognition, engulfment, phagosome formation, and destruction.
What are opsonins?
Opsonins, such as antibodies and complement component C3b, coat microorganisms to enhance their susceptibility to phagocytosis.
What are the local manifestations of inflammation?
The local manifestations of inflammation include redness, heat, swelling, and pain due to vascular changes like vasodilation and increased capillary permeability.
What are the principal systemic effects of inflammation?
The principal systemic effects of inflammation are fever, leukocytosis (increased levels of circulating leukocytes), and increased plasma proteins (acute-phase reactants).
What characterizes chronic inflammation?
Chronic inflammation is characterized by a dense infiltration of lymphocytes and macrophages, and may involve the formation of a granuloma to isolate infection.
What is resolution in wound healing?
Resolution (regeneration) is the return of tissue to nearly normal structure and function.
What is repair in wound healing?
Repair is healing by scar tissue formation.
What is healing by primary intention?
Healing by primary intention occurs when little tissue has been lost or the injured tissue is capable of regeneration.
What is healing by secondary intention?
Healing by secondary intention occurs in tissues that sustained extensive damage or are incapable of regeneration, resulting in scar formation.
What are the two phases of wound healing?
The two phases of wound healing are the reconstructive phase (where the wound begins to heal) and the maturation phase (where the healed wound is remodeled).
What factors can lead to dysfunctional wound healing?
Dysfunctional wound healing can be related to ischemia, excessive bleeding, excessive fibrin deposition, predisposing disorders (like diabetes), wound infection, inadequate nutrients, numerous drugs, or altered collagen synthesis.
What is dehiscence in wound healing?
Dehiscence is a disruption in which the wound pulls apart at the suture line.
What is a contracture?
A contracture is a deformity caused by the excessive shortening of collagen in scar tissue.
How does innate immunity function in newborns?
Neonates often have transiently depressed inflammatory function, particularly in neutrophil chemotaxis and alternative complement pathway activity.
What risks do older adults face regarding wound healing?
Older adults are at risk for impaired wound healing, usually due to chronic illnesses.
How does aging affect the immune system?
Aging causes alterations in both the innate and adaptive immune systems, affecting responses to inflammation, infection, and vaccination.
