Immunology Lecture 2_tissues Flashcards
Describe primary and secondary lymphoid organs
Primary lymphoid organs are the sites of lymphosyte production and maturation. It includes Bone marrow, thymus, and the fetal liver.
Secondary lymphoid organs are the site of immune response. it includes lymph nodes, spleen, and mucosal associated tissue
Describe what happens to the thymus as we age
As we age the thymus begins to shrink. This leads to a reduction in mature T cells and leaves elderly people more at risk of infection.
Where does lymphocyte production begin?
In the red bone marrow. B Cells and NK cells mature here. T cell precurcers travle to the thymus for maturation.
Where is the thymus located
it is a bilobed gland above the heart.
Where does T cell maturation occure?
Thymocyctes enter the thymus through small blood vessles. They mature to lymphocytes in the cortex of the thymus
Describe Hassall’s Corpuscles
They are regions in the medulla of the thymus with no known function. They are only found in a few mammals. It is believed that they may contribute to auto immunity
Where do B cells congragate for immune response
Primary follicle’s which are located in the perifery of lymph nodes
Where do T cells congragate for immune response
In the parafollicular zone (the interior of lymphnodes)
Describe red pulp and white pulp of the spleen
red pulp is the location where phagocytosis of red blood cells and antigens/microbes from the blood.
White pulp is the location of B and T cells around arterioles
What are the risks of asplenia
There is a life long risk of seriouse infection, particularly from encapsulated bacteria. often given life long dose of prophylactic antibiotics
Where is the mucosal immune system
The mucosal imune system is located in the GI, respitory, UG, and salivary glands. Encounters the more antigens and pathogens than the systemic immune system
What are peyer’s patches
they are organized areas of lymphatic tissue that lines the gut, particulalry in the ileum
Where are lymphatic vessles found
every where except cartilage, CNS, Cornea, and Epidermis
Where do the blood stream and lymph system converge
at the Thoracic duct and cisterna chyli
What are the two kinds of movment of lymphocytes?
Extravasation - cells move through unruptured vessles congragate in tissues as a result of selectins and integrins
Chemotaxis - cells attracked by chemokines. Neutrophiles move to site of infection and T/B cells migrate to areas within secondary lymphoid tissues
