Lecture 4 Flashcards
Where do white blood cells originate from?
The white blood cells are produced in the bone marrow from the haematopoietic stem cells which can divide to give precursor cells
The common myeloid precursor which gives rise to granulocytes, macrophages, dendritic cells and mast cells of the innate immune system
And the common lymphoid precursor which produces lymphocytes and NK cells
What are the macrophages in the liver?
Kupffer cells
What are the macrophages in the kidney?
Mesangial phagocytes
What are the macrophages in the brain?
Microglia
What are the macrophages in the connective tissue?
Histiocytes
What are the macrophages in the bone?
Osteoclasts
What are the macrophages in the lung?
Alveolar macrophages
What are the macrophages in the spleen?
Littoral cells
How do B cells develop?
The B cell precursor rearranges its immunoglobulin genes
Immature B cells bound to self antigen is removed from the repertoire
Mature B cell bound to foreign antigen is activated
Activated B cells give rise to plasma cells and memory cells
How do T cells develop?
T cell progenitors develop in the bone marrow and migrate to the thymus where it rearranges its T-cell receptor genes in the thymus
Immature T cells that interact strongly with self MHC molecules are removed from the repetorie
Mature T cells encounter foreign antigens in the peripheral lymphoid organs are activated
Activated T cells proliferate and migrate into peripheral sites to eliminate infection
What are the primary lymphoid organs?
Bone marrow
Thymus
Fetal liver
Bursa of fabricius (in birds)
What are the secondary or peripheral lymphoid organs?
Spleen
Lymph nodes
Gut associated lymphoid tissue, tonsils, adenoids, Peyers Patches
Where do most lymphocytes reside?
Most reside in the secondary lymphoid organs with only 10% in the circulation at a particular time
How does fluid move through the lymphatic system?
Cells are bathed in interstitial fluid (plasma), under pressure from the circulation it leaks from the capillaries into the spaces between cells 90% of this fluid returns to the circulation via the venules but 10% filters slowly through the tissues and enters minute channels (lymphatic capillaries) where it becomes lymph
Lymphatic capillaries connect to progressively larger lymphatic vessels which in turn connect to the thoracic duct where it re-enters the circulation
What is the function of peripheral lymphoid organs?
They trap antigen bearing dendritic cells to allow initiation of the adaptive immune response and provide signals to sustain circulating lymphocytes
