| Question | Answer |
| Myeloid lineage phagocytes | Derived from myeloid stem cells
Monocytes
Granulocytes
Dendritic cells |
| Dendritic cells | Found in epithelial tissues |
| Granulocytes | Neutrophils (innate immunity), eosinophils & basophils (allergic reactions & anti-parasites) |
| Monocytes | Found in most tissues, mature into macophages, central to adaptive immunity |
| eosinophils & basophils | allergic reactions & anti-parasite |
| Lymphoid lineage lymphocytes & natural killer cells | Derived from lymphoid stem cells
B cells
T Cells
NK Cells |
| B cells | recognize circulating antigens → produce antibodies |
| T cells | recognize antigen bound to MHCs on antigen presenting cells (APCs)
T helper cells
Cytotoxic T cells |
| T helper cells | CD4 |
| Cytotoxic T cells | CD8 |
| Natural killer (NK) cells | Innate immune cells
Recognize tumor & virus-infected cells |
| Central lymphoid tissues | Bone marrow & thymus
Tissues where immune cells produced & mature |
| T cells produced in ______ | marrow → migrate to thymus → proliferate & mature |
| Thymic selection | only T cells that recognized foreign (not self) antigens survive
Thymus regresses after puberty |
| B cells produced in ______ | marrow and mature there – also undergo selection |
| Peripheral lymphoid tissues | Lymph nodes |
| Lymph nodes | located where lymph vessels converge
Abundant in axiallae, groin, abdomen
flows through nodes bringing antigens |
| Antigen presenting cells exposed to antigens _____ | → activate T cells |
| T cells activated in the ____ | paracortex → proliferate → migrate to cortex |
| B cells in follicles of _____ | cortex activated → move to medulla |
| B cells mature in | medulla → release Antibodies |
| Spleen | in abdominal cavity
Filters antigens – Acts as huge lymph node |
| Other secondary lymphoid tissues | Clusters of lymphoid tissue
MALT – mucosa associated lymph tissue
Membranes of GI, respiratory, GU tracts
Peyers patches - intestines |
| General purpose cytokines | Chemicals produced by immune cells
Bind to receptors on nearby cells
Contribute to a variety of parts of the immune response |
| Chemokines | Similar to cytokines
Stimulate migration & activation of immune cells
Implicated in arthrosclerosis, Crohn disease, asthma, etc |
| Colony stimulating factors | Stimulate blood cell production in marrow |
| Epithelial barriers | Innate Immunity
Skin
Mucous membranes |
| Skin | excellent barrier & also has antibacterials (Lysozyme) |
| Mucous membranes | Mucus traps microbes → cilia remove them
GI, GU, Respiratory |
| Lung | Collectin proteins (surfactants) target pathogens for phagocytosis |
| Stomach | Defensin proteins kill bacteria by disrupting membrane |
| Cells of innate immunity | Phagocytes engulf & destroy bacteria
Neutrophils
Macrophages
Dendritic cells
NK cells |
| Macrophages | later-responding phagocytes |
| Dendritic cells | antigen presenting cells
Link innate & adaptive immune responses |
| NK cells | Lymphocytes
Recognize virus-infected & cancer cells → kill them
Have activation receptor – recognizes abnormal surface antigens
Have inhibitory receptor - recognizes self antigens
If both engage → NK cell takes not action
Cytokines induce apoptosis |
| Neutrophils | early-responding phagocytes |
