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Tutorial to answer the question:
Immediately following a break in the skin, phagocytes engulf bacteria within
the wound. This is an example of an _________ immune response which is __________
against a pathogen.
| A. |
adaptive, specific |
| B. |
innate, specific |
| C. |
innate, nonspecific |
| D. |
adaptive, nonspecific
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Tutorial
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Innate defenses begin to act very soon after the appearance
of a pathogen in the body. Innate defenses are nonspecific
– they target any pathogen. Innate defenses include:
- Skin, which excludes most pathogens from entering the
body
- Cilia in mucous membranes, which sweep out airborne pathogens
and dust
- Tears, nasal secretions and saliva, which contain bacteria-destroying
enzymes
- Specialized phagocytic cells ("phago-"=eating,
"cyte"=cell) which migrate to affected areas
and engulf pathogens.
Phagocytic cells include granulocytes (or neutrophils), macrophages,
and dendritic cells that are part of the white blood cell fraction.
Pathogens and infected cells produce chemokines, peptides that
increase the permeability of blood vessels. This permits a migration
of white blood cells toward the wound, causing the redness and
inflammation associated with infection.
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Microscopic movie of macrophages
ingesting a yeast
(567 kb)
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Adaptive immune responses are antigen-specific. Adaptive immune
responses include production of antibody and destruction of infected cells.
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