Basic Immunology: Body's Defense Against Infection

What is the typical length of E. coli bacteria?

1.8 μm

30 m

7 μm (correct)

15 to 35 cm

What is the purpose of the innate immune system?

To limit infection

To cause infection

To prevent infection (correct)

To eradicate infection

What type of acids are present in sweat?

Amino acids

Fatty acids

Nucleic acids

Lactic acid (correct)

What is the function of cilia in the lower respiratory tract?

To move mucus up toward the larynx Signup and view all the answers

What is the name of the antimicrobial peptide found in sweat?

Dermicidin Signup and view all the answers

What is the term for the barriers to infection provided by the skin and mucus membranes?

External defences Signup and view all the answers

How often can a bacterial population double in size?

Every 20 minutes Signup and view all the answers

What is the primary function of lysozyme in tears, saliva, and mucus?

To break down bacterial cell walls Signup and view all the answers

Which of the following is a function of natural killer cells?

To kill virally infected cells Signup and view all the answers

What is the primary function of interferons?

To inhibit the replication of viruses in cells Signup and view all the answers

What is the role of symbiotic bacteria in the gut?

To compete with pathogens for nutrients and sites of attachment Signup and view all the answers

What is the purpose of the highly acidic gastric acid secretions?

To destroy bacteria and toxins Signup and view all the answers

What is the role of phagocytes in the immune system?

To ingest and destroy microbes Signup and view all the answers

What is the purpose of the flow of tears, urine, saliva, perspiration, and vaginal secretions?

To prevent microbe adhesion to epithelial surfaces Signup and view all the answers

What is the term for the engulfing of bacteria by cells?

Phagocytosis Signup and view all the answers

What is the purpose of vasodilation and increased vascular permeability?

To deliver antibodies and coagulation factors from the blood into tissues Signup and view all the answers

What is the role of macrophages in inflammation?

To engulf bacteria and damaged tissue Signup and view all the answers

What is the result of the accumulation of dead phagocytes and damaged tissue?

Pus formation Signup and view all the answers

What is the function of histamine released from mast cells?

To cause vasodilation and increased vascular permeability Signup and view all the answers

What are the symptoms of inflammation?

Rubor, calor, tumor, dolor Signup and view all the answers

What is the role of prostaglandins in inflammation?

To cause vasodilation and increased vascular permeability Signup and view all the answers

What is the result of complement activation in phagocytosis?

Opsonisation Signup and view all the answers

What is the primary function of CD8+ cytotoxic T cells?

To recognize and bind to infected cells Signup and view all the answers

What is the role of MHC-II in the adaptive immune response?

To present antigens to CD4+ helper T cells Signup and view all the answers

What is the result of granzymes' action on infected cells?

Induction of apoptosis Signup and view all the answers

What is a key feature of adaptive immunity?

Specificity for particular foreign molecules Signup and view all the answers

What is the role of IL-2 in the adaptive immune response?

To induce the proliferation and differentiation of T cells Signup and view all the answers

What is the result of perforin's action on infected cells?

Lysis of the infected cell Signup and view all the answers

What is the primary function of IgG antibodies?

Neutralizes bacterial and viral toxins, enhances phagocytosis, and activates complement Signup and view all the answers

What is the function of IgA antibodies?

Protects mucus membranes against viruses and bacteria Signup and view all the answers

What is the function of IgM antibodies?

Causes agglutination and lysis of bacteria, and activates complement Signup and view all the answers

What is the function of IgE antibodies?

Found on mast cells, involved in allergic reactions Signup and view all the answers

What is Immunological Memory?

The basis for vaccination Signup and view all the answers

What is the effect of Immunological Memory on antibody production?

Serum IgG antibody titers are higher and faster on the second response Signup and view all the answers