Lymphatic System Flashcards
What are the primary organs of the lymphatic system?
generate lymphocytes from progenitor cells
bone marrow
thymus
cloacal bursa
What are the secondary organs of the lymphatic system?
site of lymphocyte activation
lymph nodes
spleen
mucosal associated lymphoid tissue
What is the function of the lymphatic system?
to protect the body against pathogenic organisms
removal and disposal of cells
What are the actions the lympathic system is involved in?
- phagocytosis via macrophages
- production of immunologically competent cells such as antigen presenting cells and T and B cells
What is the mononuclear phagocytic system?
fixed macrophages and free macrophages
What are fixed macrophages?
sinusoids of liver, spleen and lymph nodes
reticulum of bone marrow
What are free macrophages?
blood, lung and serous cavities
How does T cell differentiation come about?
bone marrow, lymphoid stem cell
Thymus
How does B cell differentiation come about?
bone marrow, lymphoid stem cell
bursa or bone marrow
What are the cells of the lymphatic system?
lymphocytes
antigen presenting cells
stromal cells
T or F: T and B cells originate from secondary lymphatic organs?
False, PRIMARY
Where do T cells migrate to from bone marrow?
thymus
T or F: B cells mature in bone marrow?
True
What is the cloacal bursa of birds?
functionally the same to mammalian bone marrow for B cell differentiation
Where is the thymus located?
medastinium, cranial to heart
What is the thymic cortex?
stains darker than medlla
greater number of lympocytes present
area of positive selection
macrophages
What is the thymic medulla?
contains epithelial reticular cells
negative selection
form Hassals corpuscles
What are Hassals corpuscles?
large central calcified cells surrounded by circles of keratinized cells
Is the thymic cortex or medulla more tightly compact?
cortex
What is the blood supply in the thymus?
arteries enter at corticomedullary junction within connective tissye
divide into arteriolies
branch into capillary network in cortex
What are educated T cells?
leave thymus
enter blood, settle in T cell areas of secondary lymphatic tissue
What is the function of lymph nodes?
filter antigens from lymph before returning it to blood stream
T or F: lymph nodes have both efferent and afferent lymph vessels
True
What are the three parts of a lymph node?
capsule
cortex
medulla
What is a lymph node cortex comprised of?
primary and secondary follices
paracortical tissue
endothelial blood vessels
What is a lymph node medulla made up of?
cords and sinus
What is a hilus?
indentation in a lymph node where arteries enter and efferent lymphatics and veins leave
What is a lymph node stroma?
reticular cells and fibers that support lymphocytes,macrophages and plasma cells
T or F: most lymphocytes migrate through lymph nodes from peripheral blood
True
What is the function of the spleen?
filters blood recovers and stores iron removes antigens from blood immune response against blood borne anitgens B and T cells stores RBC and platelets
T or F: cats do not have storage type spleen?
True
What is a spleens structure?
outer capsule=dense connective tissue
capsule=trabeculae=collagen, elastic, smooth
each trabeculae contain vein and artery
What is white pulp?
part of spleen that contains central arterioles and follicles
What is red pulp?
part of spleen that contains sinusoids
What are the two parts of the red pulp of the spleen?
parenchyma and venous sinuses
What is the parenchyma made up of?
macrophages and blood cells
B cells and T cells
How does splenic blood flow work?
in at central artery, branches to form pencillary arteries, end in capillaries, blood enters parenchyma, then to sinus system, sinuses become larger, then into splenic vein into hepatic portal vein
What is GALT?
Gut associated lymphatic tissue
What are peyers patches?
aggregated lymphatic nodules
B cells maturation
What are M cells?
specialized epithelial cells that cover peyers patches
What is BALT?
bronchiolar associated lymphoid tissue
What are tonsils?
aggregated lymphatic nodules in pharynx
no afferent vessels
Where does local production of antibodies occur?
tonsils
What are lympathic vessels?
lined by endothelial cells
absorb fluid from intersituoum, and pass it back to blood stream
Where are lympathic vessels NOT found?
eye cartilage bone or bone marrow spleen CNS
