Immunology Flashcards
First line of defense
First line of defense – any barrier that blocks invasion at the portal of entry – nonspecific
Physical barriers: skin, tears, coughing, sneezing
Chemical barriers: low pH,
lysozyme, digestive enzymes
Genetic barriers: resistance
inherent in genetic makeup
of host (pathogen cannot
invade)
Innate, humoral, cell-mediated immunity
Innate, natural defenses: present at birth, provide
nonspecific resistance to infection
Adaptive immunities: specific, must be acquired
Lymphoid nodes
Small, encapsulated, bean-shaped organs along lymphatic channels and large blood vessels of the thoracic and abdominal cavities
Thymus
High growth and activity until puberty, then begins to shrink. Site of T-cell maturation.
Spleen
Nestled below the diaphragm and left of the stomach. Structurally similar to lymph node; filters circulating blood to remove worn out RBCs and pathogens.
GALT
GALT—gut-associated lymphoid tissue (Peyer’s patches)
Eosinophils
Eosinophils – 1-3% - orange granules and bilobed nucleus; destroy eukaryotic pathogens
Neutrophils
Neutrophils – 55-90% - lobed nuclei with lavender granules; phagocytes
Macrophages
Monocytes, macrophages – 3-7% - largest of WBCs, kidney-shaped nucleus; phagocytic
Macrophages: final differentiation of monocytes
Lymphocytes
Lymphocytes – 20-35%, specific immune response
Basophils
Basophils – 0.5% - constricted nuclei, dark blue granules; release potent chemical mediators
Plasma cells
Whole blood: plasma and formed elements (blood cells)
• Serum: liquid portion of blood after a clot has formed
(minus clotting factors)
• Plasma – 92% water, metabolic proteins, globulins,
clotting factors, hormones, and other chemicals and gases
to support normal physiological functions
B and T lymphocytes
B (humoral immunity): activated B cells produce
antibodies
T cells (cell-mediated immunity): activated T cells modulate immune functions and kill foreign cells
Signs and symptoms of inflammation
Redness – increased circulation and vasodilation in response to chemical mediators
Warmth – heat given off by the increased blood flow
Swelling – increased fluid in the tissue as blood vessels dilate – edema; WBC’s, microbes, debris, and fluid collect to form pus; prevents spread of infection
Pain – stimulation of nerve endings
Pyrogen and fever
Fever is initiated by circulating pyrogens which reset the hypothalamus to increase body temperature; signals muscles to increase heat production and vasoconstriction
Components of specificity and memory of acquired immunity
Unlike the innate immune system, the adaptive immune system relies on fewer types of cells to carry out its tasks: B cells and T cells. Both B cells and T cells are lymphocytes that are derived from specific types of stem cells, called multipotent hematopoietic stem cells, in the bone marrow.
Agglutination
Ab aggregation; cross-linking cells or particles into large clumps
Opsonization
Process of coating microorganisms or other particles with specific antibodies so they are more readily recognized by phagocytes. Carried out by antibodies called “opsonins”
Neutralization
Antibodies fill the surface receptors on a virus or the active site on a microbial enzyme to prevent it from attaching
Complement Fixation
Activation of the classical complement pathway can result in the specific rupturing of cells and some viruses
Anamnestic response
renewed rapid production of an antibody following second or later contact with the provoking antigen or with related antigens.
Monoclonal antibodies
Originate from a single clone and have a single specificity for antigen
Pure preparation of antibody
Single specificity antibodies formed by fusing a mouse B cell with a cancer cell
Used in diagnosis of disease, identification of microbes and therapy
Artificial, natural, active, passive immunizations
Active immunity – results when a person is challenged with antigen that stimulates production of antibodies; creates memory, takes time, and is lasting
Passive immunity – preformed antibodies are donated to an individual; does not create memory, acts immediately, and is short term
Natural immunity – acquired as part of normal life experiences
Artificial immunity – acquired through a medical procedure such as a vaccine
Precipitation
Aggregation of particulate antigen
