Immunology Flashcards
What is self-tolerance?
The body’s immune defenses do not normally attack tissues that carry a self marker
What are the physical barriers of first line of defence?
Skin and mucosal barriers (reproductive, respiratory, digestive tract)
What are the two types of immune system?
Innate and adaptive
What immune system produces antibodies and has a memory?
Adaptive
Which type of immune system is the first to respond?
Innate
Where does hematopoiesis occur in adults?
Sternum, vertebrae, iliac bones, ribs
What cells are matured in the thymus?
T lymphocytes
What do the common lymphoid progentior cells produce?
B lymphocytes, NK cells, T lymphocytes
Where are monocytes/macrophages made?
Bone marrow
What do monocytes divide and different into?
Macrophages
What are some of the functions of macrophages (4)?
- Give off chemicals that restrict blood flow away from site of injury
- Contraction of endothelial cells
- Produce cytokines to alert other cells to the ‘danger’ and induce them to travel to the site of injury
- Phagocytotsis
What is the most abundant white blood cell?
Neutrophil
What do neutrophils do?
Phagocytosis
What type of infections do eosinophils help combat?
Parasitic infections
What other types of reactions are eosinophils involved in?
Allergy and asthma
What do mast cells contain and what does it do?
Histamine which leads to bronchospasm and vasodilation
What is the least common of the granulocytes?
Basophils
What other cell - other than mast cells - store histamine in their granules?
Basophils
Where are NK cells found?
In blood and spleen
How do NK cells bore holes in target cells?
By secreting perforin
What are non-specific humoral factors?
Within body fluids a variety of soluble substances with protective functions
What are some examples of non-specific humoral factors?
Growth inhibitors, enzyme inhibitors, lysins, complement proteins
What are the three activation pathways of the complement system?
- Classical
- Alternative
- Lectin
What is MAC?
Membrane attack complex
What does the complement system consist of?
Serum and cell surface proteins that interact with one another and other molecules in the immune system in highly regulated manner
What is the same outcome for all three of the different activation pathways of the complement system?
Lysis of the target cell and/or opsonisation of pathogens
What pathways of the complement system are effector mechanisms of the innate immune system?
Alternative and lectin
What are membrane attack complexes?
Structure formed on surface of pathogenic bacterial cells as a result of activation of one of the host’s complement pathways, it forms transmembrane channels and these channels disrupt the cell membrane of target cells causing cell lysis and death
What are some of the functions of the complement system (4)?
- Induce lysis of microbes (MAC)
- Promote phagocytosis of microbes (opsonisation)
- Stimulate inflammation - activate mast cells and neutrophils
- Also stimulate activation of B cells and Ab production
What are cytokines?
Chemicals used by cells to communicate with other cells
What is acute inflammation?
The initial response of the body to harmful stimuli
What happens during chronic inflammation?
Progressive shift in the type of cells which are present at site of inflammation and is characterised by simultaneous destruction and healing of tissue from inflammatory process
What are the functions of the lymphatic system?
Drainage of tissue, absorption and transport of fatty acids and fats, immunity
What is the route of lymphatic drainage?
Lymph –> afferent vessel –> lymph node –> efferent vessels (filtered lymph) –> lymphatic duct –> venous system –> blood
What are primary lymphoid organs?
Places where blood cells are produced and receive their ‘early training’ = bone marrow and thymus
Where are the main sites of hematopoieseis before birth?
Yolk sac, liver, spleen and bone marrow
What happens in the thymus?
Maturation of T cells
What other cells can be found in the thymus?
Macrophages, dendritic cells and thymocytes (T cell precursors)
What are the secondary lymphoid organs?
Sites of lymphocyte activation by antigens including: lymph nodes and lymphatic system, spleen, tonsils, cutaenous and mucosal immune systems
What is the function of the white pulp in the spleen?
Contains antigen presenting cells (APCs), B cells and T cells which promote the interaction requied for the efficient development of the humoral immune responses