Lymphoid Organs. Flashcards
What occurs in the lymphoid organs?
Antigens are presented to different immune components.
Do the lymphoid organs help to regulate immune responses?
Yes.
Lymphoid organs provide an environment for what?
Interactions between lymphocytes, APC’s and antigens.
Where in the developing embryo do lymphocytes come from?
The embryonic yolk sac.
The foetal liver.
The bone marrow.
Where are lymphocytes made in adult organisms?
The bone marrow.
Where in the adult body does lymphocyte differentiation occur?
The bone marrow.
Where are the 4 areas of the body that lymphocytes will develop in?
The thymus.
The bursa (only found in avians).
Peyers patches (in mammals).
The bone marrow.
What happens after lymphocytes have developed?
They travel to various parts of the body where they can respond to antigens.
What are the 4 locations of the body where mature lymphocytes will be found?
The tonsils.
The spleen.
The lymph nodes.
The peyers patches.
What name is given to the organs where lympoid development occurs?
Primary lymphoid organs.
What are secondary lymphoid organs?
The locations where lymphocytes carry out their function.
What 2 things happen to T cells in the primary lymphoid organs?
They are educated not to attack the bodies own cells.
They acquire their different antigen binding receptors (TCRs).
What does the education of lymphocytes mainly involve?
Killing any lymphocytes that recognise self antigens.
Lymphocytes should always kill what kind of antigens?
Foreign antigens.
Do lymphocytes encounter foreign antigens in the primary lymphoid tissues?
No, the only encounter foreign antigens in the secondary tissues.
What are the 2 classifications of secondary lymphoid tissue?
BALT = bronchial associated lymphoid tissue.
GALT = gut associated lymphoid tissue.
What occurs in the secondary lymph tissues?
B and T cells are educated to recognise foreign antigens.
What happens when lymphocytes encounter a foreign antigen?
They undergo differentiation and become an effector cell.
What are effector B cells known as?
As plasma cells.
What are the 2 types of effector T cells?
T helper cells (CD-4+).
Cytotoxic T cells (CD-8+).
When will T cells acquire their TCR’s?
When they leave the primary lymph tissue.
When can T cells perform their effector functions?
When they have been educated.
What is the function of CD-4 T cells?
To present antigens to B cells.
What is the function of CD-8+ T cells?
To kill infected cells and tumour cells.
