Chapter 2: Cells, Organs, Tissues Flashcards
Hematopoiesis
Formation and development of RBC and WBC
Hematopoietic stem cells
Self-renewing pluripotent stem cells which differentiate either into lymphoid or myeloid progenitor types (based on cytokines/growth factors present in environment)
Myeloid lineage cells
Become polymorphonuclear cells (granulocytes—> neutrophils and macrophages), eosinophils, basophils, dendritic cells, erythrocytes and platelets
Lymphoid lineage cells
Become lymphocytes (B cells, T cells, natural killer cells, and some dendritic cells)
Primary lymphoid organs
Where lymphocytes mature (Bone marrow for B-cells, thymus for T-cells)
Secondary lymphoid organs
Where immune cells come in contact with immunogenicity (trap antigens there and initiate immune response)
Examples: lymph nodes, spleen, adenoids, associated lymphoid tissue
Lymphatic system
Plasma become interstitial fluid, which can drain off as lymph. This lymph goes through one-way valves, is processed/ filtered for antigens, and then is returned to the subclavian vein via the thoracic duct.
Tertiary lymphoid tissue
A site of active infection and immune activity. These sites can develop organized lymphoid micro-environments, including B-cell follicles
B-cell follicle
Clusters of B-cells
Germinal centers
Mass of reproducing B-cells
Follicular dendritic cells (FDC’s)
Dendritic cells specific to the lymph nodes
Stromatolites cells
Non-hematopoietic cells that support the growth and differentiation of hematopoietic cells
Hematopoietic growth factors
Colony stimulating factors (IL-3/ multi, macrophage, granulocyte, granulocyte myocyte) and erythropoietin
Monocytes
Immature macrophages circulating in the blood vessels.
Inflammatory: respond to infection
Macrophages
Mononuclear phagocyte in tissue. Participates in innate and adaptive immunity
Neutrophils
Phagocytic with short life span. Innate immunity; first to arrive at site of inflammation (high #= first sign of active infection)
Eosinophils
Contains cystaloid (toxic) granules Active in immune response to parasites and tumors, and late-phase allergic responses
Basophils
Non-phagocytic PMNC which circulates in blood stream. Important in allergic reactions. Contain inflammatory/toxic compounds in their granules (histamine)
Mast cells
Found in tissues; involved in allergic responses. Also contain toxic/ inflammatory granules
Dendritic Cells
Also knows as “interdigitating reticular cells”. Phagocytize and process antigens, then present them to T-cells to activate them and initiate adaptive immunity
