Organs Of The Immune System Flashcards
What immunity is mediated by lymphocytes found within lymphoid organs?
Adaptive immunity
What is it called when an immune system attacks itself?
Autoimmune
What is the role of lymphocytes when they reside in secondary lymphoid organs?
Encounter and respond to foreign antigens
What are the major secondary lymphoid organs?
Lymph nodes, spleen, bone marrow, tonsils, and peyer’s patches within intestines
What are the primary lymphoid organs?
Thymus, bursa, peyer’s patches, and bone marrow
What is the role of the primary lymphoid organs?
Develop lymphocytes
What is the ectododermal junction or endoderm the origin of?
Primary lymphoid organs
What is the time of development for the primary lymphoid organs?
Early in embryonic life
What happens when you remove a primary lymphoid organ?
Loss of lymphocytes
What type of response to an antigen is produced by primary lymphoid organs?
Unresponsive
What is the origin of secondary lymphoid organs?
Mesoderm
When are secondary lymphoid organs developed?
Late in fetal life
What is the effect of removing secondary lymphoid organs?
No or minor effects
What type of response do secondary lymphoid organs have to antigens?
Full response
Where is the thymus located?
Cranial thoracic cavity
What does the thymus produce?
Hormones
As you age, what happens to the number of lymphocytes?
They decrease
If you remove an animals thymus, what happens to the thymic hormones?
Decrease in hours
If you remove an animals thymus, what happens to the blood t cells?
Decrease in 1 week
If you remove an animals thymus, what happens to the spleen t cells?
Decrease in 1 month
If you remove an animals thymus, what would happen if the animal had a skin graft surgery?
The animals immune system would not reject it as it would if the animal had it’s thymus
If you remove an animals thymus, what happens to the antibodies?
They decrease slightly
What are 2 examples of congenital athymic animals?
Nude mouse and Mexican hairless dog
Why do hairless rats skin grafts survive if the don’t have a thymus?
There is no cellular immune response to reject the graft
What is an example of a primary lymphoid tissue of a chicken?
Bursa of Fabricius
What is the main effect of a thymectomy?
Decrease in cellular immune response
What is the major effect of a bursectomy?
Decrease in antibodies
What are group 1 animals that have Peyer’s patches?
Ruminants, pigs, horses, dogs, humans
What are group 2 animals that have Peyer’s patches?
Primates, rabbits, rodents
For group 2 animals, what is probably the source of B cells?
Bone marrow
Do lymphocytes mature in organs?
No
What system is made of open-ended vessels that return extravascular fluid from the periphery to the heart and blood?
Lymphatic system
What are distributed throughout the lymphatics that act as series of small filtering stations?
Lymph nodes
What is the main job of the dendritic cells?
Present pathogen to t and B cells to develop an immune response
What secondary lymphoid tissue has a high presence of dendritic cells?
High endothelial venule
Why is bone marrow the secondary immune response after a vaccine?
Some cells differentiate memory cells which migrate and survive in the bone marrow
Where is the primary immune response after a vaccine?
Lymph node or spleen
What does MALT stand for?
Mucous-associated lymphoid tissue
If a cat has a skin infection on its paws, what lymph node will likely be swollen?
Axillary
What arises from bone marrow stem cells?
All lymphocytes
