Flashcards in The Immune System (Lyons) Deck (25):
what are the formed elements in blood?
RBC, leukocytes, megakaryocyte fragments, platelets
what are the organic/inorganic substances in blood
plasma proteins (albumin, fibrinogen, globulins)
AA, vitamins, hormones, nutrients, wastes, etc.
structure of RBC
8 micrometers in diameter
what are platelets?
fragments of megakayocyte cells in bone marrow
whats the function of platelets?
hemostasis. doesn't leave the blood
what are the granulocytes
neutrophils aka polymorphonuclear cell
Neutrophils: size, morphology, function
segmented nucleus, 3-5 lobes
chemotactically attracted to inflammation sites; phagocytosis of bacteria
Eosinophils: size, morphology, function
bilobed nucleus, large cytoplasm, eosinophilic lysosomes
chemotactically attracted to inflammation sites by eosinophil chemotactic factor released by mast cells or parasites; neutralize histamine; inhibit mast cells; phagocytose Ag-Ab complex in allergic response
Basophils: size, morphology, function
lobed nucleus, masked by large basophilic granules in cytoplasm
similiar to mast cells (secrete same substances, same primary/secondary IgE response)
large, eccentric, horseshoe shaped nucleus
differentiate into macrophages in CT, dendritic cells, osteoclasts/blasts of bone/cartilage
Natural Killer cell function
innate immune system lymphocytes that are cytolytic
Lymphocytes: size, morphology, function
small (6-9 micrometers), medium (10-12 micrometers), large (12-18 micrometers)
round, dense heterochromatic nucleus; larger the cell, larger the nucleus and more cytoplasm
cell surface receptors facilitate cell migration, response to foreign and self Ag
innate vs. adaptive immunity
innate - neutrophils/macrophages phagocytose Ag
adaptive - lymphocytes neutralize and destory Ag
cell mediated immunity vs. antibody mediated immunity
CMI - t cells directly attack intracellular Ag
AMI - extracellular Ag destroyed by Ab secreted by B cell that helps destroy/neutralize Ab
what are the primary lymphoid organs and where do B cells and T cells mature?
Thymus (T cells)
Bone marrow (B cells)
what are the secondary lymphoid organs?
lymph nodes, spleen, diffuse lymphatic tissue
how does the thymus development in comparison to the rest of the body?
greatest size during fetal stage, then grows more slowly. regresses and thymic tissue replaced by adipocytes
what are the two lobules of the thymus and their morphology
cortex - dark staining, isolated compartment supported by reticular epithelia
medulla - light staining, continuous
what surrounds the thymus?
loose CT that blends w/ surrounding CT
what are trabeculae
connective tissue that is continuous with the capsule
how are the 6 types of reticular epithelial cells distributed?
three in cortex
three in medulla
what are the two main functions of reticular epithelia cells?
barrier - keeps Ag out while T cells mature
T cell maturation - releases hormones and expresses MHC molecules for selection
what are hassall's corpuscles, what substances do they release?
densely packed whorls of reticular epithelial cells
release IL-4, IL-7, cytokine thymic stromal lymphopoietin (TSLP)
what does thymic stromal lymphopoietin (TSLP) do?
increases dendritic cell ability to convert naive thymocytes to regulatory T cell lineage