Lymphatics (ex.III) Flashcards
What are the 3 primary lymphatic organs and what cells do they develop?
- Bone Marrow - B cells
- Bursa of fabricius - B cells
- Thymus - T cells
What are the 3 secondary lymphatic organs?
- lymph nodes (filters lymph)
- spleen (filters blood)
- mucosal associated lymphoid tissue
The function of the lymphatic system is to protect the body against ________ and help in removal and disposal of ________.
protect against pathogenic organisms
remove degenerating cells
What are the antigen presenting cells?
dendritic cells, macrophages, B cells
Where can fixed macrophages be found?
- sinudoids of liver
- sinusoids of spleen
- sinusoids of lymph nodes
- reticulum of bone marrow
- thymus
Where can free macrophages be found?
- blood (monocytes)
- lung
- serous cavities
(build up of fluid attracts macrophages)
Which cells of the lymphatic system usually produce cytokines that create an environment conducive for cell development? They also have a background structural function.
stromal cells
reticular cells
What types of cells are present in a nodule of the Cloacal Bursa?
- lymphocytes
- B-cells
- macrophages (to take up apoptotic cells)
Where in the body is the source of pluripotent stem cells(B and T cells)?
bone marrow
B cells mature in bone marrow
T cells migrate to thymus to mature
The thymus is surrounded by a connective tissue ____ which sends in ____ that divide the organ into lobules.
capsule
septae
Where in the thymus does positive selection occur?
“good” lymphocytes are chose to further develop to T cells
cortex
Where are Tingible body macrophages found and what is their purpose?
thymus
they phagocytose and eliminate dead or apoptotic T cells
Where in the thymus does negative selection occur?
“bad” lymphocytes are broken down
medulla
What are large central calcified or degenerated cells surrounded by concentric circles of keratinized cells called?
thymic/Hassall’s corpuscles
these are unique to the thymus and more obvious in the medulla
Where do arteries enter the thymus?
corticomedullary junction within the septa
the arteries branch into a capillary network in the cortex
Mature T cells leave the thymus via the _____ at the ___ junction and enter the blood to travel to secondary lymphatic tissues.
postcapillary venules
corticomedullary junction
What is the only lymphatic organ with both afferent and efferent lymph vessels as well as sinuses containing lymph?
lymph node
Where do arteries enter and veins leave the lymph node?
hilus
Where do afferent lymphatics enter the lymph node?
Where do efferent lymphatics leave the lymph node?
afferent: multiple sinuses along the capsule
efferent: hilus
In lymph nodes ____ extends from the capsule into the cortex and medulla providing structural support.
trabeculae
What 3 cell types are supported by the lymph node stroma?
lymphocytes
macrophages (antigen presentation)
plasma cells
____ are specialized vessels located in the paracortex that can only infiltrate lymphocytes in the lymph nodes.
high endothelial venules (HEV)
What path does lymph travel in filtration through lymph nodes starting with the afferent vessel ending with the efferent vessel?
afferent -> marginal (sudcapsular) sinuses -> corticle (trabecular) sinses -> medullary sinuses -> efferent
What type of lymph node follicle is activated? Why has it become activate?
secondary follicle
antigens have been presented
