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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.

  • What do the three complement activation pathways have in common?
  • Explain autocrine, paracrine, and endocrine signals.
  • Name two important inflammation-eliciting mediators.

Part 2

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.

  • Which aspects of the innate immune system could be contributing to Angela’s airway constriction?
  • Why was Angela treated with antihistamines?
  • Why would the doctor be interested in levels of cytokines in Angela’s blood?

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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

Key concepts and summary

  • Numerous chemical mediators produced endogenously and exogenously exhibit nonspecific antimicrobial functions.
  • Many chemical mediators are found in body fluids such as sebum, saliva, mucus, gastric and intestinal fluids, urine, tears, cerumen, and vaginal secretions.
  • Antimicrobial peptides (AMPs) found on the skin and in other areas of the body are largely produced in response to the presence of pathogens. These include dermcidin, cathelicidin, defensins, histatins, and bacteriocins.
  • Plasma contains various proteins that serve as chemical mediators, including acute-phase proteins , complement proteins , and cytokines .
  • The complement system involves numerous precursor proteins that circulate in plasma. These proteins become activated in a cascading sequence in the presence of microbes, resulting in the opsonization of pathogens, chemoattraction of leukocytes, induction of inflammation, and cytolysis through the formation of a membrane attack complex (MAC) .
  • Cytokines are proteins that facilitate various nonspecific responses by innate immune cells, including production of other chemical mediators, cell proliferation, cell death, and differentiation.
  • Cytokines play a key role in the inflammatory response, triggering production of inflammation-eliciting mediators such as acute-phase proteins, histamine , leukotrienes, prostaglandins , and bradykinin .

Fill in the blank

________ are antimicrobial peptides produced by members of the normal microbiota.


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________ is the fluid portion of a blood sample that has been drawn in the presence of an anticoagulant compound.


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The process by which cells are drawn or attracted to an area by a microbe invader is known as ________.


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Short answer

Differentiate the main activation methods of the classic, alternative, and lectin complement cascades.

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What are the four protective outcomes of complement activation?

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Questions & Answers

microbial genetics mcqs
kajal Reply
what is the importance of learning microbiology in nursing?
Grace Reply
it's about child-care?
the way of common children disease? hmm 🤔🤔
how do you mean child care?
Was ist die Wichtigkeit beim Lernen von Mikrtobiologie in der Pflege? Es ist notwendig dass die Schwestern allgemein und auch die Kinderschwestern eine Ausbildung in der Mikrobiologie erfahren. Sie sind in ihrem Beruf gefo
you need to know the truth about diseases. the microbes are have immunity to some pharmacy.
is base pairing rule states that adenine pair with thymine cytosine pair with guannie what will be the complementry strand to acggt
KooL Reply
introduction to microbiology
Shweta Reply
Study the life of microorganisms present in the environment their survivals etc..
Microscopic organisms, commonly known as microorganisms or microbes, are found all around us and even inside our bodies. The category 'Microbes' includes a massive range of organisms including bacteria, fungi, viruses, algae, archaea and protozoa.
fermented foods likely benefited ancestors to preserve foods and make other foods like milk, cheese, and bread using microbes.
Zinnia Reply
the evidence that I would support the statement regarding ancient people ideas that disease was transmitted by things they could not see is by the discoveries under a microscope. Many microbiologists have discovered certain diseases caused by microbes.
plz give the information about glyoxylate cycle
kamini Reply
what type of information?
I need medical microbiology mcqs books for Mbbs
for pakistani mbbs or other?
what is microbial soup?
Osborn Reply
😃😂funny question isn't it?!!! sorry for inconvenience 😊
most bacterial pathogens that cause disease in humans are classified in terms if their preferable ph as
Beesan Reply
what is micro
Kabul Reply
extremely small in size
almost invisible to the naked eye
invisible sized objects
invisible sized object or specimens.which is used to see in only the microscope that specimens or objective called the micro
small organism that can be seen by use of Microbes
why do you need to study microorganisms
what is microbiology?
Green Reply
microbiology is a branch of biology .it deals with the study of microorganisms life cycle , uses, disadvantages,and it impact in any other fields .which is used to view in microscope .
Microbiology is the study of microorganisms, those being unicellular, multicellular, or acellular. Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology and parasitology. 
In short , it is the study of micro organisms and types , characteristics.
can you explain the structure of rna in detail
Dhanalakshmi Reply
RNA is of many types....like mRNA,tRNA,rRNA,snRNA,guideRNA..etc .
but generally RNA is single stranded
It contains adenine guanine cytosine , instead of thymine it contains uracil.
ribonucleic acid present in RNA.. where as in DNA it is deoxyribonucleic acid...and ribonucleotide is present in RNA
RNA is a blue print of DNA. it has the information from DNA....and we can predict the base panirs in DNA if we have the RNA....copy of that DNA
can either have positive or negative polarity
Diatoms need..... With the help of which they can construct their beautiful cell wall
Prathmesh Reply
Microbial growth curve shows a.... Curve.
Shambhuraj Reply
diminishing curve
It represents the decreasing growth of an organism.
what is meant by reverse isolation in tuberculosis treatment?
Swetha Reply
why do we study microbiology
Microbiology is the way of gaining knowledge about those organisms which are surround us but we can't see them with our naked eye,such organisms called microorganisms..We can see them only under microscope.
from our birth to death microorganisms are with us in the environment as well as on our body which are called Microflora.
Microfloras are non pathogenic
Practice MCQ 5

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