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Another inflammatory mediator, bradykinin , contributes to edema , which occurs when fluids and leukocytes leak out of the bloodstream and into tissues. It binds to receptors on cells in the capillary walls, causing the capillaries to dilate and become more permeable to fluids.
To relieve the constriction of her airways, Angela is immediately treated with antihistamines and administered corticosteroids through an inhaler, and then monitored for a period of time. Though her condition does not worsen, the drugs do not seem to be alleviating her condition. She is admitted to the hospital for further observation, testing, and treatment.
Following admission, a clinician conducts allergy testing to try to determine if something in her environment might be triggering an allergic inflammatory response. A doctor orders blood analysis to check for levels of particular cytokines. A sputum sample is also taken and sent to the lab for microbial staining, culturing, and identification of pathogens that could be causing an infection.
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[link] provides a summary of the chemical defenses discussed in this section.
| Chemical Defenses of Nonspecific Innate Immunity | ||
|---|---|---|
| Defense | Examples | Function |
| Chemicals and enzymes in body fluids | Sebum from sebaceous glands | Provides oil barrier protecting hair follicle pores from pathogens |
| Oleic acid from sebum and skin microbiota | Lowers pH to inhibit pathogens | |
| Lysozyme in secretions | Kills bacteria by attacking cell wall | |
| Acid in stomach, urine, and vagina | Inhibits or kills bacteria | |
| Digestive enzymes and bile | Kill bacteria | |
| Lactoferrin and transferrin | Bind and sequester iron, inhibiting bacterial growth | |
| Surfactant in lungs | Kills bacteria | |
| Antimicrobial peptides | Defensins, bacteriocins, dermicidin, cathelicidin, histatins, | Kill bacteria by attacking membranes or interfering with cell functions |
| Plasma protein mediators | Acute-phase proteins (C-reactive protein, serum amyloid A, ferritin, fibrinogen, transferrin, and mannose-binding lectin) | Inhibit the growth of bacteria and assist in the trapping and killing of bacteria |
| Complements C3b and C4b | Opsonization of pathogens to aid phagocytosis | |
| Complement C5a | Chemoattractant for phagocytes | |
| Complements C3a and C5a | Proinflammatory anaphylatoxins | |
| Cytokines | Interleukins | Stimulate and modulate most functions of immune system |
| Chemokines | Recruit white blood cells to infected area | |
| Interferons | Alert cells to viral infection, induce apoptosis of virus-infected cells, induce antiviral defenses in infected and nearby uninfected cells, stimulate immune cells to attack virus-infected cells | |
| Inflammation-eliciting mediators | Histamine | Promotes vasodilation, bronchoconstriction, smooth muscle contraction, increased secretion and mucus production |
| Leukotrienes | Promote inflammation; stronger and longer lasting than histamine | |
| Prostaglandins | Promote inflammation and fever | |
| Bradykinin | Increases vasodilation and vascular permeability, leading to edema |
________ are antimicrobial peptides produced by members of the normal microbiota.
bacteriocins
________ is the fluid portion of a blood sample that has been drawn in the presence of an anticoagulant compound.
plasma
The process by which cells are drawn or attracted to an area by a microbe invader is known as ________.
chemotaxis
Differentiate the main activation methods of the classic, alternative, and lectin complement cascades.
What are the four protective outcomes of complement activation?
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