Exam 3 Lymphatic System Flashcards
What are the primary organs of the lymphatic system?
- Bone marrow
- Cloacal bursa/ bursa of fabricius
- Thymus
What are the secondary organs of the lymphatic system?
- Lymph nodes
- Spleen
- mucosal associated lymphoid tissue
What is the function of the lymphatic system?
to protext the body against pathogenic organisms and their products and to help in the removal and disposal of cells undergoing natural or induced degenerations
What are the 2 mechanisms of action of the lymphatic system?
- phagocytosis
2. production of immunologically competent cells
Where are fixed macrophages found?
sinusoids of: Liver spleen lymph node Reticulum of bone marrow
Where are free macrophages found?
Blood
lung
serous cavities
Cells that capture, process and present protein fragments from extracellular antigens
APCs
What are the 3 APCs?
- Dendritic cells
- Macrophages
- B-cells
Where does T cell differentiation occur?
Thymus
Where does B cell differentiation occur?
bursa or bone marrow
What are the 2 types of stromal cells found in the lymphatic system?
Reticular and epithelial reticular cells
What is the cloacal bursa?
aka bursa of fabricus
dorsal wall of the cloaca, functionally equivalent to mammalian bone marrow for b cell differentiation
Where is the thymus located?
in the mediastinum just cranial to the heart
Which part of the thymus is the area of positive selection?
Cortex
Which part of the thymus is the area of negative selection?
Medulla
Large central calcified or degenrated cells surrounded by concentric circles of keratinized cells
Hassall’s corpuscles
What is the corticomedullary junction?
Area of the thymus where arteries enter
Organ that filters antigens from lymph before returning it to bloodstream
Lymph Nodes
What is the only lymphatic organ with both afferent and efferent lymph vessels and sinuses containing lymph?
Lymph nodes
The dense, irregular connective tissue of the lymph node
Capsule
Extend from capsule into the cortex and medulla of lymph nodes
Trabeculae
reticular cells and fibers that support lymphocytes, macrophages, and plasma cells, located in lymph nodes
Lymph node stroma
Lymph vessels open into the _______
Subscapsular sinus
Trace the path of lymph through the lymph node!
Afferent vessel– Marginal (subscapsular) sinuses– Cortical (trabecular) sinuses– medullary sinuses– efferent vessel
What are the 3 zones of the germinal center of a seondary follicle?
- Dark zone (DZ)
- apical light zone (LZ)
- Marginal zone (MZ)
What happens when thoracic duct is ruptured?
Chylothorax
what are the 5 functions of the spleen?
- filters blood
- samples/removes antigens from blood
- Mounts immune response against blood borne antigens
- hematopoiesis in fetus
- stores RBCs and platelets
Which species does not have a storage- type spleen?
cats
What are the 2 portions of Red Pulp in the spleen?
- parenchyma
2. venous sinuses
What makes up the parencyma of the red pulp
macrophages
What makes up the venous sinuses in red pulp?
long endothelial cells and basement memb.
What does the parenchyma of white pulp contain?
b cells and t cells
What are the mucosal associated lymphoid tissues?
- GALT
- BALT
- Tonsil
- Ocular
- Urogenital
- Mammary
What are GALT?
Gut-associated lymphatic tissue
What are the 5 GALTs?
- Solitary and aggrigated lymph nodes
- Intraepithelial lymphocytes
- subepithelial lymphocytes
- Plasma Cells
- Macrphages
What are Peyer’s patches?
Aggregated lymphatic nodules located in the small intestine
Blind-ended lymphatic capillaries within intestinal vili of small intestine
Lacteals
What are M-Cells?
Specialized epithelial cells found in peyer’s patch that secrete contento on the lymphocytes and macrophages
Aggregated lymphatic nodules in pharynx
Tonsils
T/F tonsils do not contain lymphatic vessels.
T
Where are lymphatic vessels not located?
eye, cartilage, bone, spleen, CNS
T/F. The flow of lymph from periphery to heart is bidirectional?
F. Unidirectional
What prevents backflow in lymphatic vessels?
One way valves
