Podcast
Questions and Answers
What is the key role of the thymus in T-cell maturation?
What is the key role of the thymus in T-cell maturation?
- Proliferation of T lymphocytes in the medulla
- Expression of CD4, CD8, and a TCR in arriving T lymphoblasts
- Selective removal of T cells reactive against self-antigens (correct)
- Production of cytokines for T-cell maturation
Where in the thymus do mature T lymphocytes exit by passing through the walls of venules and efferent lymphatics?
Where in the thymus do mature T lymphocytes exit by passing through the walls of venules and efferent lymphatics?
- Cortex
- Microvasculature
- Medulla (correct)
- Tight layer of TECs
What is the outcome of positive selection in the thymus?
What is the outcome of positive selection in the thymus?
- Binding to MHC molecule results in cell death
- Recognition of self-antigens promotes proliferation
- Increased expression of CD4 and CD8 (correct)
- Survival dependent on not recognizing self-antigen
In the thymic medulla, what determines the survival of pre-T lymphocytes?
In the thymic medulla, what determines the survival of pre-T lymphocytes?
Which cells within the thymus present MHC molecules with antigens to pre-T lymphocytes in the cortex?
Which cells within the thymus present MHC molecules with antigens to pre-T lymphocytes in the cortex?
What happens to pre-T lymphocytes in the thymus that recognize self-antigens during negative selection?
What happens to pre-T lymphocytes in the thymus that recognize self-antigens during negative selection?
What is the main function of squamous thymic epithelial cells (TECs) in the cortex of the thymus?
What is the main function of squamous thymic epithelial cells (TECs) in the cortex of the thymus?
What prevents unregulated exposure of thymocytes to antigens in the thymus?
What prevents unregulated exposure of thymocytes to antigens in the thymus?
What is the role of stellate TECs in the thymus?
What is the role of stellate TECs in the thymus?
Which cell type in the thymus express MHC class II molecules and secrete cytokines for T-cell development?
Which cell type in the thymus express MHC class II molecules and secrete cytokines for T-cell development?
What is the function of the cortical epithelial cells in the thymus during T-cell maturation?
What is the function of the cortical epithelial cells in the thymus during T-cell maturation?
Which feature distinguishes squamous thymic epithelial cells (TECs) from stellate TECs in the thymus?
Which feature distinguishes squamous thymic epithelial cells (TECs) from stellate TECs in the thymus?
What is the main function of Hassall corpuscles in the thymic medulla?
What is the main function of Hassall corpuscles in the thymic medulla?
Which cell type is less densely packed in the thymic medulla compared to the cortex?
Which cell type is less densely packed in the thymic medulla compared to the cortex?
What is the primary role of squamous cortical TECs in the thymus?
What is the primary role of squamous cortical TECs in the thymus?
What is the unique feature of thymic corpuscles in the medulla?
What is the unique feature of thymic corpuscles in the medulla?
Which structure forms a boundary between the cortex and medulla in the thymus?
Which structure forms a boundary between the cortex and medulla in the thymus?
What characterizes secondary nodules in lymphoid organs?
What characterizes secondary nodules in lymphoid organs?
