Assignment 1 Flashcards
role of immune system in host defense
provides defense against foreign antigens
define tolerance
adaptive immunity of the body distinguishing self from non-self such that it destroys non-self and not self
consequences of loss of tolerance
leads to autoimmunity, a disorder in which self molecules are interpreted as foreign and hence trigger immune responses
difference between central and peripheral tolerance
B cells undergo central tolerance in the bone marrow and T cells undergo central tolerance in the thymus. Peripheral tolerance are tolerance induction of those that escaped tolerance induction in the bone marrow or thymus
properties of antigens
foreign, chemically complex, molecular weight greater than 6kD
molecules that are most immunogenic in descending order
proteins > polysaccharide > nucleic acids > lipids
three terms that are used to refer to the component of the antigen with which receptors on immune cells interact
epitope, antigenic determinant, determinant
three chemical barriers to infections
lysozyme, spermine, acidic pH of stomach
two physical barriers to infections
skin and mucosal linings
4 defining characteristics to adaptive immune system
exquisite specificity, lag time, memory, and adaptivity
4 defining characteristics of innate immune system
no exquisite specificity, no lag time, no memory, no adaptivity
cells of innate immunity
phagocytes (macrophages and neutrophils), natural killer (NK) cells, dendritic cells, mast cells, basophils, eosinophils
cells of adaptive immunity
lymphocytes (T and B cells)
components of secondary lymphoid tissue
lymph nodes, tonsils and adenoids, spleen, and malt (mucosal associated lymphoid tissue)
what are primary lymphoid tissue
bone marrow and thymus
role of bone marrow and thymus
Under the influence of the local microenvironment some of the lymphoid precursors will give rise to mature B cells, while other lymphoid precursors will leave the bone marrow and migrate to the thymus and differentiate to various T cell subsets
role of secondary lymphoid tissue
major sites of adaptive immune responses - initial immune response is determined by the mode of antigen entry
what happens in the lymph nodes
afferent lymphatics penetrate the connective tissue that encapsulates the lymph node and empty their contents into the subcapsular sinuses
difference between primary and secondary follicles of lymph nodes
secondary have germinal centers while primary does not
what do primary follicles contain
mature resting B cells
what is in a germinal center
antigen activated B cells
types of cells present in between and below follicles
T cells interspersed with dendritic cells
what does the medulla contain
dendritic cells, macrophages, plasma cells
what does the nodes consist of
outer cortex, medulla, paracortex
