Chapter 14: Med Surg Flashcards
immunity
a state of responsiveness to foreign substances such as microorganisms and tumor proteins; fx: defense, homeostasis, surveillance
homeostasis
damaged cellular substances are digested and removed, but the body’s different cell types remain unchanged
surveillance
mutations continually arise, but are normally recognized as foreign cells and destroyed
active immunity
takes awhile to develop, but long lasting
passive immunity
short lived because the host did not synthesize the antibodies and does not retain memory cells for the antigen
antigen
body recognizes a foreign substance and elicits an immune response; most composed of protein
thymus gland
central (primary) lymphoid organ- shrinks with age and is important in the differntiation and maturation of t lymphocytes
bone marrow
central (primary) lymphoid organ- produces RBCs, WBCs, and platelets
lymphoid tissue
found in submucosa of the respiratory, genitourinary, and GI tract- protects body surface from external microorganisms e.g. tonsils
spleen
primary site for filtering foreign substances from blood and major site of immune responses to blood-borne antigens
lymphnodes
filtrate foreign material brought to site and circulate lymphocytes
mononuclear phagocytes
monocytes & macrophages; capture through phagocytosis and the macrophage bound antigen is presented to lymphocytes which triggers an immune response
B lymphocytes
produced in bone and differentiate into plasma cells which produce antibodies (immunoglobulins)
T lymphocytes
migrate from bone marrow to thymus, compose 70%-80% of lymphocytes and provide immunity to intracellular viruses, tumor cells, and fungi; long term immunity
T cytotoxic cells
CD8 attack antigens on cell membrane of foreign pathogens and destroy, antigen specific and sensitized by exposure to the antigen
T helper cells
CD4 regulate cell-mediated immunity and the humoral antibody response
natural killer cells
involved in cell-mediated immunity, large lymphocytes, do not require prior sensitization for activation, recognize and kill virus-infected cells, tumor cells, and transplanted grafts
antibodies
immune globulins produced by lymphocytes in response to antigens
dendritic cells
capture antigens at sites of contact with the external environment and then transport the antigen to a T cell with specificity for the antigen and activate the immune response
cytokines
soluble factors secreted by WBCs that act as messengers between cell types and instruct cells to alter their proliferation, differentiation, secretion, or activity
interferons
type of cytokine that help the body’s natural defenses attack tumors and viruses and enhance natural killer cells
what is the first antibody formed by humoral immunity?
IgM formed by the primary immune response (4-8 days after initial exposure); forms antibodies to ABO blood antigens
cell-mediated immunity
t cells. macrophages, and natural killer cells that are initiated through specific antigen recognition by t cells; memory cells- protects against fungus, intracellular viruses, chronic infections, and tumor cells
humoral immunity
antibody-mediated immunity produced by b lymphocytes that have memory cells- protects against bacteria, extracellular viruses, respiratory pathogens, and GI pathogens
examples of when humoral response is initiated
anaphylactic shock, atopic diseases, transfusion reactions, bacterial infections
what is the second antibody formed by humoral immunity?
IgG formed by the secondary response (1-3 days after second exposure and is more rapid & stronger) ONLY ONE TO CROSS PLACENTA
examples of when cell-mediated response is initiated
TB, fungal infections, contact dermatitis, graft rejection, destruction of cancer cells
IgA
found in body secretions and lines mucous membranes to protect body surfaces
IgD
found in plasma, assists differentiation of B lymphocytes
IgE
found in plasma and interstitial fluid & causes symptoms of allergic reaction
effects of aging on the immune system
more tumors, greater chance of infection, thymic involution, decreased cell-mediated immunity, delayed hypersensitivity reaction, decreased autoantibodies
what is relatively unaffected in the immune system of older people?
bone marrow
anergy
common in older people, lack of or dimished reaction to an antigen
type 1 hypersensitivity
IgE mediated, anaphylactic reaction, highly sensitized to pollen, food, drugs, dust
mediators to type 1 hypersensitivity
histamine, mast cells, leukotrienes, prostaglandins; short acting and reversible
locus
where the gene resides on the chromosome
allele
one of two or more alternative forms of a gene that codes inherited characteristics
dominant allele
gene that is expressed in the phenotype of a heterozygous individual, allele that is fully expressed
recessive allele
lacks the ability to express itself, no noticeable effect on the phenotype
transcription
messenger RNA is synthesized from a single strand of DNA
mitosis
results in two identical daughter cells and before duplication, each cell receives an extra replica of chromosomes from parent cell
meiosis
oocytes and sperm contain only a single copy of each chromosome
crossing over
genetic material is exchanged between homologous chromosomes in the cell; some traits from mom, some from dad
autosomal dominant disorders
mutation of single gene pair, has variable expression (people may have same mutated gene, but different symptoms), and incomplete penetrance (skips generations or a completely new gene) e.g. Huntington’s disesase
Autosomal recessive disorders
mutations of two gene pairs, if you only receive one half of the gene, you do not have the disease, but you are a carrier e.g. Cystic fibrosis, sickle cell disease
X-linked recessive disorders
usually only effect men, daughters of effected male will be carrier, sons of affected male are unaffected unless mother is a carrier e.g. hemophilia