Immune Response

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Vocabulary• Immunology- the study of host defense mechanisms

• Immunity- ability of the host to protect itself against foreign organisms. Resistance to disease.

• Antigen (Ag)- is a foreign substance that can elicit specific immune response (IR) when is immunogenic

• Antibody (Ab)- protein produced by the body’s immune system when it detects harmful substances called antigens

• White blood cells (leukocytes)- chief function is to protect the body against microorganisms causing disease and fight infection when it occurs. They are bigger than red blood cells.

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Leukocytes (White Blood Cells (WBC))

• Protect the body against microorganisms, toxins, & tumor cells. • remove dead cells & debris from body

• Complete cells with all organelles• Stained & further identified by

• size• shape of the nucleus• presence/absence of granules• colors taken up by their granules

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• Normal Blood Smear– WBCs

account for less than 1% of blood’s volume

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White Blood Cells (WBC)

• 5 Major types of WBC– Neutrophils– Eosonophils– Basophils– Lymphocytes (T and B Cells)– Monocytes

• Divided into two categories– Granuolocytes and Agranuolocytes

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Granuolocytes

• Neutrophils– are the most common WBC in peripheral blood. – Circulate in blood 7-10 hrs before migrating into tissue

• Live only a few days (1-2 in tissue)– “front line of innate defense”

• 1st WBCs to show up at an infection site– Increase in # used as an indicator of infection – Extravasate in inflammation rxn– Active phagocytes– Fungi

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Granuolocytes

• Eosonophils– Defend the body in parasitic infections• Tapeworms, hookworms, pinworms

– Function in phagocytosis– Account for less than 5% of WBC– Involved in allergies• Reduce or control inflammatory response by destroying

histamine– Red bi-lobed nucleus with red granules

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Granuolocytes

• Basophils– Least common WBC in blood – Non phagocytic– Function as “sirens” for inflammation and allergy• Produce histamine (a vasodilator) and heparin • Large, histamine containing granules that stain dark

purple to blue