27 Questions
Where do B cells primarily collect in the lymph nodes?
Outer cortex
What is the non-immunological role of the red pulp in the spleen?
Filters damaged or aged red cells
What structures in the spleen form the periarteriolar lymphatic sheath (PALS)?
Fibrous partitions (SEPTAE)
Where do T cells primarily collect in the lymph nodes?
Paracortical areas
During B cell development, immature B cells mature under local influences and are educated to not respond or bind to self molecules while arranging their B cell receptors. This process is an example of:
Negative selection
What is the function of lymphatics in the lymphatic system?
To transport lymphocytes and other leukocytes around the body
Which molecules do lymphocytes bind to when using the lymphatics to migrate around the body?
Adhesion molecules expressed by endothelial cells
What happens to immature B cells that do not leave the bone marrow during their maturation process?
They undergo apoptosis
What is the primary function of lymphocytes in the lymphatic system?
To migrate between tissues, primary and secondary lymphoid organs
Which type of vessels allow for the movement of cells from tissues to lymph nodes in the immune system?
Afferent vessels
What is the main purpose of high endothelial venules (HEV) in the context of lymph nodes?
To allow lymphocytes and antigens to enter the lymph nodes
What is the role of adhesion molecules (homing receptors) in the movement of leukocytes through the body?
To allow binding to molecules expressed by endothelial cells
What is the function of efferent vessels in the lymphatic system?
Draining lymph from the lymph nodes back into the blood circulatory system
Which type of cells recirculate between tissues, primary and secondary lymphoid organs via the blood and a network of vessels called the lymphatics?
Lymphocytes
T cells primarily collect in the outer cortex of the lymph nodes.
False
The medulla of the lymph nodes contains T cells and antigen-presenting cells.
False
Secondary follicles in the lymph nodes contain smaller cells associated with macrophages forming germinal centers.
False
Lymph nodes show decreased turnover of lymphocytes after antigen exposure.
False
The thymus is the first organ to produce lymphocytes and provides an environment for B cell maturation and education.
False
The thymic nurse cells affect thymocyte development in the medulla of the thymus.
False
Only 50% of original thymocytes make it through the thymus into circulation as naïve T cells.
False
Lymph nodes are surrounded by a reticulum and have three main areas: cortex, paracortical area, and medulla.
True
The function of efferent vessels in the lymphatic system is to allow cells of the immune system to get together with antigen to start specific immune responses.
False
High Endothelial Venules (HEV) in lymph nodes are responsible for the entry of lymphocytes and antigen into the lymph nodes.
True
The primary function of lymphocytes in the lymphatic system is to prevent backflow through lymphatics using adhesion molecules.
False
The traffic of cells through the body to specific areas, such as lymph nodes, is called random movement.
False
Afferent lymphatic vessels carry antigens and cells from lymph nodes to tissues.
False
Study Notes
- The lymphatic system facilitates movement of lymphocytes and other leukocytes between tissues and primary and secondary lymphoid organs
- Lymphocytes move through the body using a network of vessels called lymphatics, which are in close association with blood vessels
- Smooth muscle cell movement and backflow prevention valves regulate the flow of lymph in lymphatics
- Lymphocyte homing (migration) occurs via binding of adhesion molecules on lymphocytes to those on endothelial cells lining blood vessels
- Lymph nodes are small, bean-shaped tissues at junctions of major lymphatic vessels, surrounded by a capsule, and have three main areas: cortex, paracortical area, and medulla
- Afferent lymphatics carry antigen and cells from tissues to lymph nodes, and efferent lymphatics drain back into the blood circulatory system via the thoracic duct
- High endothelial venules (HEV) in lymph nodes allow lymphocytes and antigen to enter the lymph nodes
- Secondary lymphoid follicles in lymph nodes contain germinal centers with lots of cell proliferation
- The spleen is a secondary lymphoid organ with both non-immunological and immunological functions
- The spleen filters damaged or aged red cells, and lymphocytes enter and leave mainly via the blood stream
- Periarteriolar lymphatic sheaths and associated clusters of lymphocytes form lymphatic follicles or nodules in the spleen.
Explore the regulation of cell movement in the lymphatic system and its association with arterial pressure, smooth muscle cell movement, backflow prevention valves, and lymphocyte homing. Understand the non-random movement of leukocytes and their adhesion molecules.
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