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Primary Lymphoid Organs definitions Flashcards

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Primary Lymphoid Organs definitions
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  • Hematopoiesis

    The process of blood cell formation, including the production of T and B lymphocytes in the red bone marrow.
  • Lymphocytopoiesis

    The formation of lymphocytes, specifically T and B cells, originating in the red bone marrow.
  • Immunocompetent

    The state of being capable of carrying out an effective immune response against specific pathogens.
  • Thymus

    A bilobed organ in the mediastinum essential for T cell maturation and selection, part of the lymphatic, immune, and endocrine systems.
  • Mediastinum

    The region in the upper chest behind the sternum, between the lungs, and above the heart, where the thymus is located.
  • Blood-thymus barrier

    A barrier formed by thymic epithelial cells preventing antigens in the blood from disrupting T cell maturation in the thymus.
  • Trabeculae

    Inward capsular extensions of dense irregular connective tissue dividing the thymus lobes into smaller lobules.
  • Lobules

    Smaller compartments within each lobe of the thymus, containing an outer cortex and an inner medulla.
  • Outer cortex

    The region in thymic lobules where premature T cells begin their maturation process.
  • Inner medulla

    The region in thymic lobules containing mature T cells, marked by lighter staining in micrographs.
  • Thymic corpuscles

    Concentric whorls of thymic epithelial cells in the inner medulla, involved in regulatory T cell development.
  • Regulatory T cells

    A special type of T cell developed in the thymus, important for preventing autoimmune diseases.
  • Adipose tissue

    Fatty tissue that accumulates in the thymus as it atrophies with age, replacing thymic tissue.
  • Thymic epithelial cells

    Specialized cells in the thymus forming the blood-thymus barrier and thymic corpuscles, secreting signaling molecules.
  • Thymic atrophy

    The process of the thymus decreasing in size and activity over time, with tissue replaced by fibrous and fatty tissue.