Exam III - Lymphatic System Flashcards
What are the primary lymphatic organs?
- bone marrow
- cloacal bursa/bursa of fabricus (birds only)
- thymus
What are the secondary lymphatic organs?
- lymph nodes
- spleen
- mucosal associated lymphoid tissue
What is the function of the lymphatic system?
to protect the body against pathogenic organisms and their products and to help in the removal and disposal of cells undergoing natural and induced degenerations
Where do B cells mature?
bone marrow
Identify the arrows marked ‘A’ in this H&E section of the canine thymus
septae
Identify the arrows marked ‘B’ in this H&E section of the canine thymus
cortex
Identify the arrows marked ‘C’ in this H&E section of the canine thymus
medulla
In the thymic cortex, __________ phagocytose and eliminate dead T cells. They are frequent near the medulla.
Tingible body macrophages (also called starry sky macrophages)
large, central calcified or degenerated cells surrounded by concentric circles of keratinized cells in the thymic medulla:
thymic corpuscles, or Hassal’s corpuscles
The left half of this H&E section of canine thymus would be referred to as the ________. The right half would be the __________.
Identify the labeled structures.
The left half of this H&E section of canine thymus would be referred to as the cortex (with tightly packed small lymphocytes). The right half would be the medulla (less compact).
A - macrophage (can tell due to the space surrounding it)
B - Hassal’s corpuscles
What is the function of lymph nodes?
to filter antigens from lymph before returning it to the bloodstream
What are the arrows pointing to in this H&E section of a canine thymus?
Hassal’s corpuscles (or thymic corpuscles)
Remember, these corpuscles are characteristic of the thymus!
____________ are where lymphocytes can leave the blood stream and enter into the lymph nodes
High endothelial venules
Identify the area labeled ‘A’ in this H&E section of a lymph node.
Cortex
Identify the area labeled ‘B’ in this H&E section of a lymph node.
medulla
Identify the structure labeled ‘C’ in this H&E section of a lymph node.
Which type of cell will be found here primarily?
Follicle; B-cells
In this H&E section of a tonsil, is this a primary or a secondary lymphoid follicle? How can you tell?
Also, label A and B, biatch!
This is a secondary follicle. You can tell because of the very defined marginal zone surrounding the germinal center.
A - marginal zone
B - germinal center
When stimulated by antigen, they will change histologic morphology from primary lymphoid follicles to secondary lymphoid follicles
Identify A and B in this H&E section of a subscapular sinus
A - macrophages
B - reticular cells
What type of cell do you find in the paracortex primarily?
T-cells
Identify the arrows in this H&E section of a lymph node.
high-endothelial venules (diapedesis)
Identify the regions labeled ‘A’ and ‘B’ in this H&E section of the medulla.
A - cords (dense area where cells appear to be migrating)
B - sinus
Identify the type of cell indicated by the arrow in this H&E section of a medulla sinus.
plasma cell (you can tell based on the very prominent cytoplasm)
_________ occurs when the thoracic duct is ruptured.
chylothorax
Most lymphocytes migrating to lymph nodes enter from the _____________.
Most lymphocytes migrating to lymph nodes enter from the peripheral blood.
