18 Questions
What is the role of cortical epithelial cells in the thymus?
Secrete cytokines that promote T-cell maturation
Where do mature T lymphocytes exit the thymus from?
Venules and efferent lymphatics in the medulla
What happens to pre-T lymphocytes that recognize self-antigens during thymic selection?
Die by apoptosis
Which cell population begins to proliferate in the thymic cortex?
T lymphoblasts not expressing CD4, CD8, or a TCR
What is the purpose of positive selection in the thymus?
To allow survival based on binding to MHC molecules
What determines whether a pre-T lymphocyte will survive and advance to the thymic medulla?
Recognition of self-antigen presented by dendritic cells
What is the main function of squamous cortical TECs?
Contribute to the corticomedullary barrier
What characterizes the thymic medulla in terms of lymphocytes?
Fewer and larger, more mature lymphocytes
What is the function of Hassall corpuscles in the thymic medulla?
Contain aggregates of TECs responsible for peripheral tolerance
What distinguishes primary nodules from secondary nodules in lymphoid nodules?
Uniform cell density and staining
Which type of medullary TECs supports T lymphocytes, dendritic cells, and macrophages?
Cytoreticulum TECs
What is the unique feature of thymic corpuscles?
Size up to 100 μm in diameter
What is the main function of squamous thymic epithelial cells in the cortex of the thymus?
Forming an isolated cortical compartment by lining the connective tissue of the capsule and septa.
What is the function of stellate thymic epithelial cells in the cortex of the thymus?
Forming a cytoreticulum for macrophages and developing lymphocytes to attach to.
Which cells in the cortex of the thymus are responsible for secreting IL-4 and other cytokines that stimulate gene recombination of B cells?
Plasma cells venules
What role do squamous thymic epithelial cells play in maintaining the blood-thymus barrier?
Forming desmosomes and occluding junctions to prevent unregulated antigen exposure.
Which characteristic distinguishes stellate thymic epithelial cells from squamous TECs?
Processes containing keratin tonofilaments
Why are cortical epithelial cells in the thymus considered as antigen-presenting cells (APCs)?
Expressing MHC class II molecules in addition to MHC class I.
Learn about the role of the thymus in T-cell maturation and selection, including the secretion of cytokines by cortical epithelial cells and the exit of mature T lymphocytes from the thymus. Understand how the thymus facilitates the differentiation of T-lymphocytes and removal of T cells reactive against self-antigens.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
