Parham Chapter 1 Flashcards
immune
resistant to infection
immune system
the tissues, cells, and molecules involved in the defense of the body against infectious agents
immunity
the ability to resist infection
vaccination
the deliberate induction of protective immunity to a pathogen by the administration of killed or non-pathogenic forms of the pathogen, or its antigens, to induce an immune response
immunization
the deliberate provocation of an adaptive immune response by introducing antigen into the body
commensal species
describes a microorganism that habitually lives on or in the human body, and which normally causes no disease or harm and can even be beneficial
flora
the community of microbial species that inhabits a particular niche in the human body, such as skin, mouth, gut or vagina
pathogen
organism, most commonly a microorganism, that can cause disease.
opportunistic pathogens
microorganism that causes disease only in individuals whose immune systems are in some way compromisesd
bacteria
(singular-bacterium) diverse prokaryotic microorganisms that are responsible for many infectious diseases of humans and other animals
viruses
submicroscopic pathogens composed of a nucleic acid genome enclosed in a protein coat. They replicate only in a living cell because they do not posses all the metabolic machinery required for independent life. A viral particle is called a virion.
fungi
single-celled and multicellular eukaryotic organisms, including the yeasts and molds, that can cause a variety of diseases. Immunity to fungi involves both humoral and cell-mediated responses.
parasites
the unicellular protozoa and multi-cellular worms that infect animals and humans and live within them
opsonization
the coating of the surface of a pathogen or other particle with any molecule that makes it more readily ingested by phagocytes. Antibody and complement opsonize extra-cellular bacteria for phagocytosis by neutrophils and macrophages because the phagocytic cells carry receptors for these molecules.
opsonins
antibodies and complement components that bind to pathogens and facilitate their phagocytosis bu neutrophils or macrophages.
parasites
the unicellular protozoa and multicellular worms that infect animals and humans and live within them.
epithelium
general name for the layers of cells that line the outer surface and the inner cavities of the body
mucosal surfaces
the mucus-coated outer surfaces of tissues, such as the gut, lungs, eyes and vagina, which communicate with the external environment to provide the body with material and information. The surfaces are delicate and they are protected by the mucus.
mucus
slimy protective secretion composed of glycoproteins, proteoglycans, peptides, and enzymes that is produced by the goblet cells in many internal epithelia.
mucosa (plural- mucosae)
a mucus-secreting epithelium such as those that line the respiratory, intestinal, and urogenital tracts. the conjunctiva of the eye and the mammary glans are also in this category.
defensins
family of antimicrobial peptides 35-40 amino acids long that can penetrate microbial membranes and disrupt their integrity
innate immune response (innate immunity)
the host defense mechanisms that act from the start of an infection and do not adapt to a particular pathogen.
effector mechanisms
the physiological and cellular processes used by the immune system to destroy pathogens and remove them from the body
effector cells
lymphocytes that can act to remove pathogens from the body without the need for further differentiation
complement
set of plasma proteins that act in a cascade of reactions to attack extracellular forms of pathogens. Many of them are serine proteases. As a result of complement activation, pathogens become coated with complement components, which can either kill the pathogen directly or facilitate its engulfment and destruction by phagocytes.
cytokines
proteins made by cells that affect the behavior of other cells. Cytokines made by lymphocytes are of ten called lymphokines or interleukins (abbreviated IL). Cytokines bind to specific receptors on their target cells.
inflammation
general term for the local accumulation of fluid, plasma proteins, and white blood cells that is initiated by physical injury, infection, or a local immune response. This is also known as an inflammatory response.
endothelium
epithelium lining the interior of blood vessels
edema
abnormal accumulation of fluid in connective tissue, leading to swelling
inflammatory cells
the cells that invade tissues undergoing inflammatory response (also called inflammatory infiltrate)
adaptive immune response
the response of antigen-specific B and T lymphocytes to antigen, including the development of immunological memory
adaptive immunity
the state of resistance to infection that is produced by the adaptive immune response
clonal selection
the central principle of adaptive immunity. It is the mechanism by which adaptive immune responses derive only from individual antigen-specific lymphocytes, which are stimulated by the antigen to proliferate and differentiate into antigen-specific effector cells.
clonal expansion
production of daughter cells all arising originally from a single cell. In a clonal expansion of lymphocytes, all progeny share the same antigen specificity
immunological memory
the capacity of the immune system to make quicker and stronger adaptive immune responses to successive encounters with an antigen. Immunological memory is specific for a particular antigen and is long lived.
acquired immunity/ protective immunity
alternative term for adaptive immunity, pathogen- specific acquired as a consequence of infection or vaccination.
primary immune response (primary response)
the adaptive immune response that follows a person’s first exposure to an antigen
secondary immune response
secondary adaptive immune response
secondary response
the adaptive immune response provoked by a second exposure to an antigen. It differs from the primary response by starting sooner and building more quickly and is due to the presence of long-lived memory B cells and T cells
leukocytes
general term for a white blood cell. Lymphocytes, granulocytes, and monocytes are all leukocytes
hematopoiesis
the generation of the cellular elements of blood, including the red blood cells, white blood cells,, and platelets. These cells all originate from pluripotent hematopoietic stem cells whose differentiated progeny divide under the influence of various hematopoietic growth factors.
pluripotent hematopoietic stem cell
stem cell in bone marrow that gives rise to all the cellular elements of the blood
efferent lymphatic vessel
the single vessel in which lymph and lymphocytes leave a lymph node en route to the blood.
germinal center
area is a secondary lymphoid tissue that is a site of intense B-cell proliferation, selection, maturation, and death. Germinal centers form around follicular dendritic cell networks when activated B cells migrate into lymphoid follicles. The cellular and morphological events that form the germinal center and take place these are called the germinal center reaction.
spleen
organ situated adjacent to the cardiac end of the stomach. One function of the spleen is to remove old or damaged red blood cells from the circulation; the other is as a secondary lymphoid organ that responds to blood-borne pathogens and antigens.
encapsulated bacteria
bacteria that posses thick carbohydrate coats that them from phagocytosis. Encapsulated bacteria cause extracellular infections and can be dealt with phagocytes only if the bacteria are first coated with antibody and complement.
erythrocytes
red blood cell
megakaryocytes
large cell of the erythroid lineage, produced in the bone marrow and resident there. Megakaryocytes produce platelets.
platelets
thrombocyte; a disk-shaped structure, 2 to 4 μm in diameter, found in the blood of mammals and important for its role in blood coagulation; platelets, which are formed by detachment of part of the cytoplasm of a megakaryocyte, lack a nucleus and DNA but contain active enzymes and mitochondria.
A minute, irregularly shaped, disklike cytoplasmic body found in blood plasma that promotes blood clotting and has no definite nucleus, no DNA, and no hemoglobin. Also called blood platelet, thrombocyte.
An irregularly shaped cell-like particle in the blood that is an important part of blood clotting. Platelets are activated when an injury causes a blood vessel to break. They change shape from round to spiny, “sticking” to the broken vessel wall and to each other to begin the clotting process.
hematopoietic cells
any blood cell or its precursor cell types
bone marrow
tissue in the center of certain bones that is the major site of the generation of all the cellular elements of blood (hematopoiesis)
self renewal
the ability of a population of cells to renew itself
myeloid progenitor
stem cell in bone marrow that gives rise to granulocytes, monocytes, and macrophages
myeloid lineage
a subset of bone marrow derived cells compromising granulocytes, monocytes, and macrophages
granulocytes
white blood cells with irregularly shaped, multilobed nuclei and cytoplamic granules. There are three types of granulocytes: neutrophils, eosinophils, and basophils. They are also known as polymorphonuclear leukocytes.
Polymorphonuclear leukocytes
an alternate name given to granulocytes- neutrophils, eosinophils, and basophils- because of the varied morphology of their nuclei.
Neutrophil
phagocytic white blood cell that enters infected tissues in large numbers and engulfs and kills extracellular pathogens. Neutrophils are a type of granulocyte and contain granules that stain with neutral dyes; hence their name. They are the most abundant white blood cell.
Phagocytes
cell specialized to perform phagocytosis. The principal phagocytic cells in mammals are neutrophils and macrophages.
Pus
thick yellowish-white fluid that is formed in infected wounds. It is composed of dead and dying white blood cells (principally neutrophils), tissue debris, and dead microorganisms.
eosinophil
white blood cell that is one of the three types of granulocyte. It contains granules that stain with eosin (hence their name) and whose contents are secreted when the cell is stimulated. Eosinophils contribute chiefly to defense against parasitic infections.
basophil
white blood cell present in small numbers in the blood; it is one of the three types of granulocyte. basophils contain granules that stain with basic dyes, hence their name.
Monocytes
white blood cell with a bean shaped nucleus. It is the precursor of the tissue macrophage
Macrophages
large mononuclear phagocytic cell resident in most tissues. Macrophages are derived from blood monocytes and contribute to innate immunity and early non adaptive phases of host defense. They function as professional antigen-presenting cells and as effector cells in humoral and cell mediated immunity.
Dendritic cells
professional antigen-presenting cells with a branched, dendritic morphology. They are the most potent stimulators of T-cell responses. Also known as interdigitatingreticular cells, they are derived from the bone marrow and are distinct from the follicular dendritic cell that presents antigen to B cells.
Immature dendritic cells take up and process antigens but cannot yet stimulate T cells.
Mature or activated dendritic cells are present in secondary lymphoid tissues and are able to stimulate T cells.
Mast cell
large bone marrow derived cell resident in connective tissues throughout the body. Mast cells contain large granules that store a variety of chemical mediators including histamine. Mast cells have high affininty FCE reseptors (FceRI) that bind free IgE. Antigen binding to IgE associated with mast cells triggers mast cell activation and degranulation, producing a local or systemic immediate hypersensitivity reaction. Mast cells have a crucial role in allergic reactions.
Lymphoid progenitor
stem cell in bone marrow cell that gives rise to all lymphocytes
Lymphoid lineage
all types of lymphocytes, and the bone marrow cells that give rise to them
Large granular lymphocytes
an alternative and earlier name for the natural killer cell. Microscopic examinations revealed two types of blood lymphocytes (naive B and T cells) and the large granular lymphocytes (NK cells)
Natural killer cells (NK cells)
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Small lymphocytes
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B lymphocytes (B- cells)
an alternative name for B cell, the lymphocytes of adaptive immunity that have immunoglobulin receptors for antigen.
T lymphocytes (T-cells)
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Immunoglobulins
any of a class of proteins present in the serum and cells of the immune system, that function as antibodies.
T-cell receptors
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Cytotoxic T-cells
subset of effector T cells that kill their target cells. They express the CD8 co-receptor and recognize peptide antigen presented by MHC class I molecules. They are important in host defense against viruses and other cytosolic pathogens because they can recognize and kill the infected cells.
Helper T cells
CD4 T cells are sometimes generally known as helper cells because their function is to help other cell types to perform their roles. The term helper T cell sometimes refers to TH2 cells only, the cells that help B cells to produce antibody.
Plasma cells
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Antibodies
the secreted form of the immunoglobulin made by a B cell.
Lymphoid Organs (Lymphoid tissues)
organized tissues that contain very large numbers of lymphocytes held in a non-lymphoid stroma. The primary lymphoid organs, where lymphocytes are generated, are the thymus and bone marrow. The main secondary lymphoid tissues, in which adaptive immune responses are initiated, are the lymph nodes, spleen, and muucosa associated lymphoid tissues such as tonsils, Peyer’s patches, and the appendix.
Primary/ Central lymphoid tissues
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Thymus
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Secondary/peripheral lymphoid tissues
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Lymphatic vessels (lymphatics)
thin walled vessels that carry lymph from tissues to secondary lymphoid tissues (with the exception of the spleen) and from secondary lymphoid tissues to the thoracic duct.
Lymph
mixture of extracellular fluid and cells that is carried by the lymphatic system.
Lymphocyte recirculation
of lymphocytes, their continual migration from blood to secondary lymphoid tissues to lymph and back to the blood. An exception to this pattern is traffic to the spleen, lymphocytes both enter and leave the spleen in the blood.
Lymph node
a type of secondary lymphoid tissue found at many sites of the body where lymphatic vessels converge (unite). Antigens are delivered by the lymph and presented to lymphocytes within the lymph node where adaptive immune responses are initiated.
Draining lymph node
the lymph node to which extracellular fluid collected at a site of infection first travels.
Lymphoid follicles
more or less spherical aggregation of mainly B cells in secondary lymphoid tissues. Naive B cells must pass through the follicles for their survival, and after B cells are activated by antigen they enter the follicles where they proliferate to form a germinal center and undergo somatic hyper mutation and isotype switching
Afferent lymphatic vessels
the various vessels that bring lymph draining from connective tissue into a lymph node en route to the blood.
Gut associated lymphoid tissues (GALT)
lymphoid tissues closely associated with the gastrointestinal tract, including that palatine tonsils, Peyer’s patches in the intestine, and layers of intraepithelial lymphocytes.
Tonsils
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Adenoids
mucosa-associated secondary lymphoid tissues located in the nasal cavity
Appendix
gut associated secondary lymphoid tissue located at the beginning of the colon
Peyer’s patches
organized gut associated lymphoid tissue present in the wall of the small intestine, especially the ileum.
Bronchial associated lymphoid tissue (BALT)
the lymphoid cells and organized lymphoid tissues of the respiratory tract.
Mucosa associated lymphoid tissue (MALT)
aggregations of lymphoid cells in mucosal epithelia and in the lamina propria beneath. The main mucusa associated lymphoid tissues are the gut associated lymphoid tissues (GALT) and the bronchial associated lymphoid tissues (BALT)
M-cells
specialized cell type in intestinal epithelium through which antigens and pathogens enter gut associated lymphoid tissue from the intestines. Short for ‘micro fold cell’.
Memory cells
general term for lymphocytes that are responsible for the phenomenon of immunological memory.
Immunodeficiency diseases
group of inherited or acquired disorders in which some part or parts of the immune system are either absent or defective, resulting in failure to mount an effective immune response to pathogens.
Acquired immune deficiency syndrome (AIDS)
disease caused by infection with the human immunodeficiency virus (HIV). It involves a gradual destruction of the CD4-T cell population and increasing susceptibility to infection.
Human immunodeficiency virus (HIV)
causative agent of the acquired immune deficiency syndrome (AIDS). HIV is a retrovirus of the lentivirus family that infects CD4 T cells, leading to their slow depletion, which eventually results in immunodeficiency.
Acquired Immunity
alternative term form adaptive immunity, pathogen specific immunity acquired as a consequence of infection or vaccination.
antigen
originally defined as any molecule that binds specifically to an antibody.