adaptive immunity/immunology Flashcards
what are the functions of the lymphatic system?
- drainage of tissue
- absorption and transport of fatty acids and fats
- immunity
what do lymphatic vessels do and where are they found?
- carry fluid away from the tissues
- found in all regions of the body except the bone marrow, the CNS and tissues which lack blood vessels
- their walls are composed are composed of endothelium in which simple squamous cells overlap to form one-way valves; this allows fluid to enter the vessel but prevents it from leaving
what and where are the primary lymphoid organs?
- the places where blood cells are produced and begin early maturation
- do not take part in immune defence
- bone marrow and thymus
what is hematopoiesis?
the formation of blood cellular components.
all cellular blood components are derived from haematopoietic stem cells
what occurs in the thymus?
the site of maturation of T cells which are generated in the bone marrow
what are secondary lymphoid organs?
the sites of lymphocyte activation by antigens
what is the epitope?
the part of the antigen that the immune system recognises
what is the composition and function of the spleen?
red pulp- primary function is to filter blood of antigens, microorganisms and defective or worn-out RBCs
is separated from white pulp by the marginal zone
white pulp- mainly contains nodules full of lymphocytes. visibly embedded in red blood-rich tissue (pulp)
what are “high endothelial venues” (HEV), and where are they found?
-found in all secondary lymphoid organs except the spleen
- The HEV is the doorway through which B cells and T cells enter the secondary lymphoid organ from the blood.
- Most of the endothelial cells which line the blood vessels overlap one another like tiles on a roof and are tightly ‘glued’ together to prevent loss of blood cells into the surrounding tissue. Some fluid still escapes and is taken back into the blood system via the lymphatic system.
what are peyer’s patches?
give an example
patches of smooth cells embedded in the villi-covered cells that line the small intestine
-one example of what is known as MALT.
what are the cells called that form a layer covering peyer’s patches and what do they do?
M cells
-M cells are specialised cells that transport Ag from the lumen of the intestine to the Peyer’s patch.
what are the tonsils?
areas of lymphoid tissue on either side of the throat and are involved in defence from infection of the upper respiratory tract
what is the role of the lymphatic system in cancer?
-an important factor in the body’s response against cancer, and is also one of the most common pathways for metastasis
what are the features of adaptive immunity? (2)
- very specific
- creates immunological memory
what is a secondary response and how does this differ from the primary response?
Exposure of the immune system to a foreign antigen enhances its ability to respond to that same antigen on subsequent encounters with it. These so called secondary responses are usually much more rapid, larger and often qualitatively different to the original, primary, immune response. Immunological memory occurs in part because each exposure to a particular antigen causes an expansion in the clone of lymphocytes which react to that antigen
what is active immunity and what are the two methods by which this is obtained?
Active immunity is conferred by a host response to a microbe or microbial antigen.
- natural active (infection, lymphocytes activated)
- artificial active (injecting or taking antigens by mouth. takes time for T and B cells to be activated but gives long lasting immunity)