LATEST High acuity final test 2024

spleen -Site of destruction for injured or worn-out RBCs -Reservoir for B cells -Storage site for blood -Releases blood in times of demand antigens -capable of triggering immune response if recognized by B or T cell -3 groups: (1)Foreign to body (2)Self-markers (self-antigens) (3)Tumor markers (tumor-associate antigens) foreign antigens -Pathogens or pathogenic antigens -capable of causing disease -Bacteria, viruses, parasites, other microorganisms -Vaccines = killed or weakened form of a virus or bacteria -Transplanted tissues/ organs self antigens -All nucleated cells contain surface antigens (histocompatibility antigens or human leukocyte antigens) -Allows to distinguish self from non-self Tumor-associated Antigens -Some tumors display particular antigens -These antigens distinguish abnormal cells from normal -low levels may occur naturally -elevation may indicate an inc in abnormal cells. Innate (Natural) Immunity -Nonspecific response to recognize and attack foreign cells. -Nonadaptive -Reacts the same to all foreign cells, regardless of previous exposure -physical barriers, Skin, Mucous membranes, Chemical barriers (GI tract) neutrophils -Outnumber all other leukocytes (50-70%) -First line of defense in infection or inflammation. -Can be found at site of injury w/i 1-1.5 hrs -Responsible for formation of pus -Intracellular granules contain enzymes to break down foreign substances -Reserved in bone marrow for 5 days -6-8 hr life once released Mature vs Immature neutrophils -Mature neutrophils are referred to as "segmented cells" or "segs" (segmented nucleus) -Immature neutrophils are referred to as "bands" or "stab" -Due to band or horseshoe shaped nucleus -segs= 54-62% -bands= 3-5% Humoral Immunity -Recognition of antigens and production of specific antibodies -B lymphocytes= once stimulated by antigen, differentiate into plasma cells and memory B cells. -Plasma cells secrete protein-based antibodies (immunoglobulins) -Memory B cells= long-term immunity of previously exposed antigens humoral immunity primary response -During 48-72 hrs after initial exposure -Antigens recognized as "non-self" -Once identified, antibodies formed specific to new antigen -48-72 hrs after initial exposure, blood tests will show positive for antibodies humoral immunity secondary response -B lymphocyte memory cells recognize an antigen almost immediately -Recognition creates heightened antibody formation response Cell-Mediated Immunity -Based on activity of T lymphocytes (T cells) -T cells and macrophages directly attack antigens -T cell immunity provides protection from intracellular organisms -Viruses, fungi, parasites, Cancer cells, Foreign tissues Passive Acquired Immunity -Temporary form of immunity -Involves transferring antibodies from one individual to another -Example: neonatal immunity from mother via placenta and breast milk -Short-lived Active Immunity