adaptive immunity/immunology Flashcards
(40 cards)
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)
what is passive immunity and what are the two methods by which this is obtained?
Passive immunity is conferred by adoptive transfer of antibodies or T lymphocytes specific for the microbe.
- natural passive (mother to child through placenta or milk)
- artificial passive (ssed during potentially fatal diseases. Provides an instant response but only temporary as antibodies are not the body’s own so memory cells are not created. E.g. tetanus - injection of antitoxins given)
what is the relationship between B cells and antibodies?
- B cells are produced in bone marrow and mature into plasma cells
- Plasma cells are responsible for antibody (Ab) production
- B cells express surface immunoglobulin (sIg) which is the antigen receptor for the B cell
describe B cell tolerance
Both B Cells and T Cells can be made tolerant, but it is more important to tolerize T cells than B cells because B cells cannot make antibodies to most antigens without the help of T cells.
…what
describe the nature of antigens
any substance capable of triggering an immune response is called an antigen. can be a virus, a bacterium, a fungus, or a parasite, or even a portion or product of one of these organisms. tissues/cells from another individual, except an identical twin whose cells carry identical self-markers, also act as antigens
describe the antibody structure
has a light chain (Ag binding region; does not affect Ig class and are only two types, λ and κ ); and a heavy chain (Fc region; define CLASSES of Ig; two regions -constant and variable; five types, γ, δ, α, μ and ε.)
there are 5 different classes of antibody; what are they and what do they do?
IgM –Good at fixing compliment and opsonization
IgG – Good opsonizer
IgA – Protects mucosal surfaces, resistant to stomach acid
IgE – Defends against parasites, causes anaphylactic shock and allergies
IgD – No known Ab function
what is oponization?
Opsonization is a term that refers to an immune process where particles such as bacteria are targeted for destruction by an immune cell known as a phagocyte . The process of opsonization is a means of identifying the invading particle to the phagocyte.
what is the function of IgA in the gut?
IgA is produced in the plasma cells in the lamina propria of the mucosal tissue and binds to the poly Ig receptor at the base of an epithelial cell. The complex is transported across the epithelial cell and the bound IgA is released into the lumen by proteolytic cleavage. This process is called transcytosis.
