Lymph node pathology Flashcards
What are the Primary Lymphoid organs?
Thymus and bone marrow
What are the Secondary Lymphoid organs?
Spleen, lymph nodes, mucosa-associated lymphoid tissue
Describe the macroscopic appearance of a lymph node.
Oval shaped.
Well circumscribed.
Outer fibrous capsule.
Veins and arteries at the hilum of the node deliver blood.. Lymphatics also leave here
Where does lymph flow through a node, from afferent to efferent lymphatic duct?
Afferent vessels enter through the capsule, into subcapsular sinuses, cortical sinuses, run into the medulla, leave via efferent lymphatics at the hilum.
What are medullary cords?
Extensions of mainly T-cells in the medulla.
What are the three main regions into which the lymph node is divided? and which cells predominate in these areas?
Paracortex Primary follicle Mantle zone Medullary cords Sinuses
What will you find in the Paracortex?
Naive T cells
High endothelial venules
Interdigitating dendritic cells
What will you find in the Primary follicle?
Naive B cells
Follicular dendritic cells
T cells
What will you find in the mantle zone?
Naive B cells
What will you find in the medullary cords?
Small T and B lymphocytes
Immunoblasts
Plasma cells
What will you find in the sinuses?
Lymph
Macrophages
Small T and B lymphocytes
Eosinophils
What are the sinuses lined by?
Endothelial cells
What sort of immune response could be observed in the paler area of germinal centre?
Humoral immune response
Which cells are responsible for driving the differentiation of B cells into B effector cells?
Follicular dendritic cells and T cells
Where does the final differentiation of B cells occur?
In the medullary cords
What are B cells called as they leave the follicle? Why?
Immunoblasts.
Called this because they are immature - final differentiation in the medullary cords.
After appropriate stimulation, naive B lymphocytes will undergo clonal expansion and differentiate. Where does this take place? and what cells do they become?
Mantle zone.
Centrobasts - centrocytes - immunoblasts.
What are two broad categories of Lymphadenopathies?
“Reactive’ inflammatory and infection.
Neoplastic.