Immune Response

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. Antigen are molecules found on the surface of cells, viruses, fungi, or bacteria. Antibodies are also produced when immune system mistakenly considers healthy tissue a harmful substance (autoimmune disorders). Leukocytes are present in peripheral blood as well as in the lymphatic system

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

Normal Blood Smear WBCs account for less than 1% of blood’s volume

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 Peripheral blood is the flowing, circulating blood of the body. It carries nutrients to all organs and systems of the body. Also carry cellular waste from cells to excretory system.

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

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

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