RNC Infectious diseases UPDATED
ACTUAL Exam Questions and CORRECT
Answers
Host defense mechanisms - CORRECT ANSWER - Overall functions of the immune
system.
a. Defense—resistance to infection by microorganisms.
b. Homeostasis—removal of worn-out cells.
c. Surveillance—perception and destruction of mutant cells.
2. Components of the immune system. a. The nonspecific mechanisms, which include
phagocytosis, the inflammatory response, and several amplification systems including
complement, coagulation, and kinin systems.
b. The specific immune responses, which consist of cell-mediated (T cell) and humoral (B cell)
systems. (1) Both are interdependent and interrelated; for example, the activation of the
complement system by immunoglobulins (IgM and IgG), or the production of chemotactic
factors and other lymphokines, plays a significant role in the whole inflammatory response.
(2) Nonspecific immune mechanisms—function without prior exposure, identified early in
gestation, functional development at 32 to 33 weeks.
c. Embryologic development (Table 32-1). (1) The maturation of specific immune responses
begins in utero during the 7th to the 12th weeks of gestation.
(2) Progenitor cells (stem cells) are initially located in the yolk sac, fetal liver, and bone marrow
of the developing embryo.
,d. Depending on the type of microchemical environment surrounding the tissue, the stem cells
will differentiate along at least two pathways: (1) The hematopoietic.
(2) The lymphopoietic. (a) The lymphopoietic system develops along two independent pathways
leading to morphologically and functionally distinct populations of immune systems: (i) The
thymus-derived or T system of cell-mediated immunity whose principal effector cells are the T
lymphocytes.
(ii) The bursal-dependent or B system of humoral or antibody-mediated immunity, which is
displayed by the B lymphocytes.
(3) The thymus gland is derived from epithelium of
Humoral Immunity - CORRECT ANSWER - 1. Immunoglobulin (McCance and Huether,
2002; Polin et al., 2001).
a. Humoral immunity is a specific antibody-mediated response that functions most effectively if
there has been previous exposure.
b. Antibodies are derived from B cells, which have been activated by T cells and antigens (Fig.
32-1).
(1) B cells mature and are stored in lymph tissue and bone marrow.
(2) B cells also produce memory cells that recognize antigens on subsequent exposures and
initiate an antibody response.
(3) Antibody functions include: (a) Recognition of bacterial antigens.
(b) Neutralization or opsonization of foreign substances, rendering them susceptible to
phagocytosis.
2. Types of immunoglobulin. a. Immunoglobulin G (IgG). (1) Major immunoglobulin of serum
and interstitial fluid.
(2) Provides immunity against bacterial and viral pathogens.
, (3) Placental transfer to the fetus is either an active or a passive process.
(4) Increases gradually until 40 weeks of gestation (majority is passed in the third trimester).
(5) Decreased levels in preterm infants, proportional to their gestational age.
(6) Decreased levels in postmature and small for gestational-age infants, suggesting inhibition of
transfer with placental damage.
b. Immunoglobulin M (IgM). (1) Does not cross the placental barrier.
(2) Synthesis begins early in fetal life, with detectable levels at approximately 30 weeks of
gestation.
(3) Levels may increase (>20 mg/ml) with intrauterine infection.
(4) Serum levels rapidly increase after birth.
c. Immunoglobulin A (IgA). (1) Is the most common immunoglobulin in the gastrointestinal and
respiratory tracts and is secreted in human colostrum and human milk.
(2) Does not cross the placental barrier.
(3) Intrauterine synthesis is minimal in an uninfected fetus.
(4) Does not beco
ACTUAL Exam Questions and CORRECT
Answers
Host defense mechanisms - CORRECT ANSWER - Overall functions of the immune
system.
a. Defense—resistance to infection by microorganisms.
b. Homeostasis—removal of worn-out cells.
c. Surveillance—perception and destruction of mutant cells.
2. Components of the immune system. a. The nonspecific mechanisms, which include
phagocytosis, the inflammatory response, and several amplification systems including
complement, coagulation, and kinin systems.
b. The specific immune responses, which consist of cell-mediated (T cell) and humoral (B cell)
systems. (1) Both are interdependent and interrelated; for example, the activation of the
complement system by immunoglobulins (IgM and IgG), or the production of chemotactic
factors and other lymphokines, plays a significant role in the whole inflammatory response.
(2) Nonspecific immune mechanisms—function without prior exposure, identified early in
gestation, functional development at 32 to 33 weeks.
c. Embryologic development (Table 32-1). (1) The maturation of specific immune responses
begins in utero during the 7th to the 12th weeks of gestation.
(2) Progenitor cells (stem cells) are initially located in the yolk sac, fetal liver, and bone marrow
of the developing embryo.
,d. Depending on the type of microchemical environment surrounding the tissue, the stem cells
will differentiate along at least two pathways: (1) The hematopoietic.
(2) The lymphopoietic. (a) The lymphopoietic system develops along two independent pathways
leading to morphologically and functionally distinct populations of immune systems: (i) The
thymus-derived or T system of cell-mediated immunity whose principal effector cells are the T
lymphocytes.
(ii) The bursal-dependent or B system of humoral or antibody-mediated immunity, which is
displayed by the B lymphocytes.
(3) The thymus gland is derived from epithelium of
Humoral Immunity - CORRECT ANSWER - 1. Immunoglobulin (McCance and Huether,
2002; Polin et al., 2001).
a. Humoral immunity is a specific antibody-mediated response that functions most effectively if
there has been previous exposure.
b. Antibodies are derived from B cells, which have been activated by T cells and antigens (Fig.
32-1).
(1) B cells mature and are stored in lymph tissue and bone marrow.
(2) B cells also produce memory cells that recognize antigens on subsequent exposures and
initiate an antibody response.
(3) Antibody functions include: (a) Recognition of bacterial antigens.
(b) Neutralization or opsonization of foreign substances, rendering them susceptible to
phagocytosis.
2. Types of immunoglobulin. a. Immunoglobulin G (IgG). (1) Major immunoglobulin of serum
and interstitial fluid.
(2) Provides immunity against bacterial and viral pathogens.
, (3) Placental transfer to the fetus is either an active or a passive process.
(4) Increases gradually until 40 weeks of gestation (majority is passed in the third trimester).
(5) Decreased levels in preterm infants, proportional to their gestational age.
(6) Decreased levels in postmature and small for gestational-age infants, suggesting inhibition of
transfer with placental damage.
b. Immunoglobulin M (IgM). (1) Does not cross the placental barrier.
(2) Synthesis begins early in fetal life, with detectable levels at approximately 30 weeks of
gestation.
(3) Levels may increase (>20 mg/ml) with intrauterine infection.
(4) Serum levels rapidly increase after birth.
c. Immunoglobulin A (IgA). (1) Is the most common immunoglobulin in the gastrointestinal and
respiratory tracts and is secreted in human colostrum and human milk.
(2) Does not cross the placental barrier.
(3) Intrauterine synthesis is minimal in an uninfected fetus.
(4) Does not beco
