Foundations in Immunology 2 Flashcards
Functions of the Lymphoid Organs + The Roles of T Lymphocytes
<p>What are functions of the lymphatic system?</p>
<p>Drainage of tissues</p>
<p>Absorption and transport of fatty acids and fat</p>
<p>Immunity</p>
<p>What is the lymphatic system?</p>
<p>Network of tubes that carry clear fluid called lymph</p>
<p>How does lymph move through the lymphatic system?</p>
<p>By contraction of skeletel muscles</p>
<p>What eventually happens to the fluid in the lymphatic system?</p>
<p>Enters the blood after entering the right lymphatic duct or thoracic duct</p>
<p>What happens to molecules in the interstitual space that are too big to pass through cappilary walls?</p>
<p>They pass into the lymphatic system which has more permeable walls</p>
<p>What are some lymph nodes?</p>
<p>Cervical</p>
<p>Axillary</p>
<p>Bronchial</p>
<p>Abdominal</p>
<p>Inguinal</p>
<p>What are the two kinds of lymph vessels?</p>
<p>Afferent</p>
<p>Efferent</p>
<p>What prevents backflow in lymph vessels?</p>
<p>Valves</p>
<p>What are the two lymphatic ducts?</p>
<p>Right lymphatic duct</p>
<p>Thoracic duct</p>
<p>What is the path that lymph being drained from interstitual space takes?</p>
<ol> <li>Lymph</li> <li>Afferent vessel</li> <li>Lymph node</li> <li>Efferent vessel (filtered lymph)</li> <li>Lymphatic duct</li> <li>Venous system</li> <li>Blood</li></ol>
<p>What are the 3 phases of immune defence?</p>
<ol> <li>Recognition of danger</li> <li>Production of specific weapon</li> <li>Transport of weapon to the site</li></ol>
<p>Where are white blood cells produced and recieve their early training?</p>
<p>Primary lymphoid organs</p>
<p>What are some primary lymphoid organs?</p>
<p>Bone marrow</p>
<p>Thymus</p>
<p>What happens to bone marrow as you get older?</p>
<p>You have less because long bones get filled with fat</p>
<p>What is the site of maturation of T cells?</p>
<p>Thymus</p>
<p>What kinds of cells are found in the thymus?</p>
<p>Macrophages</p>
<p>Dendritic cells</p>
<p>Numerous thyrocytes (T cell precurders)</p>
<p>What is a secondary lymphoid organ?</p>
<p>Site of lymphocyte activation by antigen</p>
<p>What are examples of secondary lymphoid organs?</p>
<p>Lymph nodes and lymphatic system</p>
<p>Spleen</p>
<p>Tonsil</p>
<p>Cutaneous immune system</p>
<p>Mucosal immune system</p>
<p>What is the spleen composed of?</p>
<p>Red pulp</p>
<p>White pulp (lymphocytes)</p>
<p>What are functions of the spleen?</p>
<p>Filter blood</p>
<p>APLs, B cells and T cells promote interactions for development of humoral immune response</p>
<p>What are functions of lymph nodes?</p>
<p>Filter and purify lymph</p>
<p>99% of antigens are removed here</p>
<p>In response to antigen detection T and B cells are stimulated and adaptive immune response initiated</p>
<p>Maintain and produce B cells and house T cells</p>
What does the structure of a lymph node look like?
<p>Where are payer's patches found and what do they do?</p>
<p>Small intestine, prevents the gorwth of pathogenic bacteria</p>
<p>What are payer's patches covered by?</p>
<p>A layer of M cells</p>
<p>What are M cells?</p>
<p>Transport antigens from the lumen of the intestine to the payer's patch, then carried to lymph then lymph node</p>
<p>What are tonsils involved in?</p>
<p>Defence from infection of the upper respitory tract</p>
<p>What is lymphoma?</p>
<p>Caner of the lymphatic system</p>
<p>What is one of the most common pathways for the spread of cancer?</p>
<p>Lymphatic system</p>
<p>What are T cells derived from?</p>
<p>Bone marrow</p>
<p>What are MHC1 and MHC2?</p>
<p>Proteins that express antigens on their surface (antigen presenting cells)</p>
<p>Where is MHC1 found?</p>
<p>On every cell</p>
<p>Where is MHC2 found?</p>
<p>On macrophages and dendritic cells</p>
<p>What are T cells responsible for?</p>
<p>Cell mediated immunity and assisting B cells</p>
<p>What do cell surface receptors in the T cell receptors (TCR) recognise?</p>
<p>Antibodies when bound to MHC</p>
<p>What are different T cells?</p>
<p>Helper of CD4+T cells</p>
<p>Cytotoxic or CD8+T cells</p>
<p>What do helper T cells do?</p>
<p>Stimulate B cells to produce antibodies</p>
<p>What do cytotoxic T cells do?</p>
<p>Work similar to natural killer cells, destroying the pathogen</p>
<p>What is the process of the origin of T cells?</p>
<ol> <li>Immature in bone marrow and head to thymus</li> <li>Mature in thymus, where receptor markers are given to them</li> <li>Head to secondary lymphoid organ</li></ol>
<p>What is T cell selection?</p>
<p>T cells must learn not to recognise out own self antigens, restricted to recognise antigen in association with out own MHC</p>
<p>What does T cell selection happen?</p>
<p>Thymus</p>
<p>What are the two types of T cell seleciton?</p>
<p>Positive selection</p>
<p>Negative selection</p>
<p>What happens during positive selection?</p>
<p>T cells are presented with self MHC on epithelial cells (if they recognise they survive = positive selection ) strength not too strong or too weak </p>
<p>If they do not recognise it they are destroyed by apoptosis</p>
<p>(tests immature)</p>
<p>What happens during negative selection?</p>
<p>T cells are presented with dendritic cells, if they recognise self antigens very STRONGLY they are destroyed by apoptosis</p>
<p>(tests mature)</p>
<p>What does MHC1 do?</p>
<p>Presents virally induced peptides to killer T cells to triger cytotoxic response</p>
<p>What does MHC2 do?</p>
<p>Found on macrophages, B cells, T cells and presents exogenously produced antigen to helper T cells to activate macrophages and B cells</p>
<p>What do helper T cells do?</p>
<p>They cannot kill, they activate and direct other immune cells</p>
<p>What do cytotoxic T cells do?</p>
<p>Release perforin when exposed to infected cells</p>
<p>Creates a pore</p>
<p>Releases granzyme B that enters pores and enduces apoptosis</p>
<p>What do memory T cells arise from?</p>
<p>Memory T cells arise from both differentiated and partially differentiated T cells</p>
<p>What do memory T cells allow?</p>
<p>Potential for further differentiation on reexposure to antigen</p>
<p>What is the difference between Th1and Th2cells?</p>
<p>Th1cells are a cellular response and produce memory cells</p>
<p>Th2cells are a humoral response and result in antibodies</p>
<p>What can a Th1/Th2 imbalance be caused by?</p>
<p>Genetic factor</p>
<p>Environmental factor</p>
<p>What can an imbalance between Th1 and Th2 cells cause?</p>
<p>Asthma</p>
