URS 6030 EXAM 2 | Questions with
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Complete Solution | Graduate Nursing
| Advanced Practice | Pass Guaranteed
- A+ Graded
**[DOMAIN 1: IMMUNE SYSTEM FUNCTION & DISORDERS - 45 Questions]**
* *Question 1**
Which leukocyte is the most numerous and serves as the first responder during bacterial
infections?
A. Eosinophil
B. Basophil
C. Neutrophil **[CORRECT]**
D. Lymphocyte
* *Rationale:** Neutrophils constitute 50-70% of circulating leukocytes and are the first cells to
arrive at sites of bacterial infection. They are highly phagocytic and contain granules with
antimicrobial substances. Eosinophils primarily respond to parasites and allergic reactions.
Basophils release histamine during allergic responses. Lymphocytes mediate adaptive immunity
but arrive later in the inflammatory response.
* *Question 2**
A patient presents with a WBC count of 3,200/mm³. What condition does this indicate?
A. Neutrophilia
B. Leukopenia **[CORRECT]**
C. Leukocytosis
D. Eosinophilia
* *Rationale:** Leukopenia is defined as a WBC count below 4,000/mm³ (normal range:
5,000-10,000/mm³). This places the patient at increased risk for infections. Neutrophilia refers to
elevated neutrophils. Leukocytosis is elevated total WBC count. Eosinophilia indicates
increased eosinophils, often seen in parasitic infections or allergies.
* *Question 3**
Where do B lymphocytes mature?
A. Thymus
B. Spleen
C. Bone marrow **[CORRECT]**
,D. Lymph nodes
* *Rationale:** B cells mature in the bone marrow (hence "B" for bone marrow). T cells mature in
the thymus. The spleen and lymph nodes are secondary lymphoid organs where immune
responses are initiated, but they are not sites of lymphocyte maturation.
* *Question 4**
Which immunoglobulin is the most abundant in serum and provides passive immunity to the
fetus?
A. IgA
B. IgM
C. IgE
D. IgG **[CORRECT]**
* *Rationale:** IgG comprises approximately 80% of serum immunoglobulins and is the only
antibody class that crosses the placenta, providing passive immunity to the newborn. IgA is
found in secretions. IgM is the first antibody produced in response to infection. IgE is involved in
allergic reactions.
* *Question 5**
Which cells are responsible for killing virus-infected cells and tumor cells without prior
sensitization?
A. B cells
B. Helper T cells
C. Natural Killer (NK) cells **[CORRECT]**
D. Eosinophils
* *Rationale:** NK cells are part of the innate immune system and can recognize and destroy
virus-infected cells and tumor cells without prior exposure or antigen presentation. This
distinguishes them from cytotoxic T cells, which require antigen presentation via MHC Class I
molecules.
* *Question 6**
MHC Class I molecules present antigens to which cells?
A. CD4+ T cells
B. CD8+ T cells **[CORRECT]**
C. B cells
D. Macrophages
* *Rationale:** MHC Class I molecules are expressed on all nucleated cells and present
endogenous antigens (viral peptides, tumor antigens) to CD8+ cytotoxic T cells. MHC Class II
molecules, found on antigen-presenting cells, present exogenous antigens to CD4+ helper T
cells.
,* *Question 7**
Which cell type becomes macrophages when they enter tissues?
A. Neutrophils
B. Monocytes **[CORRECT]**
C. Basophils
D. Lymphocytes
* *Rationale:** Monocytes circulate in blood and differentiate into macrophages upon entering
tissues. Macrophages are highly phagocytic and serve as antigen-presenting cells. Neutrophils
remain as neutrophils. Basophils and lymphocytes do not transform into macrophages.
* *Question 8**
Which lymphoid organ filters blood and removes old erythrocytes?
A. Thymus
B. Lymph nodes
C. Spleen **[CORRECT]**
D. Tonsils
* *Rationale:** The spleen filters blood, removes senescent red blood cells, and serves as a site
for immune activation. Lymph nodes filter lymph. The thymus is a primary lymphoid organ for T
cell maturation. Tonsils are part of MALT (mucosa-associated lymphoid tissue).
* *Question 9**
Which antibody class is found in tears, saliva, and breast milk?
A. IgG
B. IgA **[CORRECT]**
C. IgM
D. IgD
* *Rationale:** IgA is the primary antibody in secretions (tears, saliva, breast milk, respiratory
and GI secretions), providing mucosal immunity. Secretory IgA prevents pathogen attachment to
mucosal surfaces. IgG dominates serum antibodies. IgM is the first response antibody. IgD
functions in B cell activation.
* *Question 10**
Helper T cells express which surface marker?
A. CD8
B. CD4 **[CORRECT]**
C. CD56
D. CD19
* *Rationale:** Helper T cells are CD4+ T cells that recognize antigens presented by MHC Class
II molecules on antigen-presenting cells. CD8 is expressed on cytotoxic T cells. CD56 is an NK
cell marker. CD19 is a B cell marker.
, * *Question 11**
Which immunoglobulin indicates a recent or current infection?
A. IgG
B. IgM **[CORRECT]**
C. IgA
D. IgE
* *Rationale:** IgM is the first antibody produced during a primary immune response, appearing
within 3-5 days of infection. Its presence indicates acute or recent infection. IgG appears later
and persists for long-term immunity. IgA and IgE are not primary indicators of recent infection.
* *Question 12**
Which chemical barrier in the stomach helps prevent infection?
A. Mucus
B. Hydrochloric acid **[CORRECT]**
C. Lysozyme
D. Cilia
* *Rationale:** Gastric hydrochloric acid creates a pH of 1-3, destroying most ingested
pathogens. Mucus is a physical barrier. Lysozyme is found in tears and saliva. Cilia are
mechanical barriers in the respiratory tract.
* *Question 13**
What is the primary function of regulatory T cells (Tregs)?
A. Kill infected cells
B. Produce antibodies
C. Suppress immune responses **[CORRECT]**
D. Present antigens
* *Rationale:** Regulatory T cells (Tregs) suppress immune responses to prevent autoimmunity
and maintain tolerance to self-antigens. They are crucial for immune homeostasis. Cytotoxic T
cells kill infected cells. B cells produce antibodies. Dendritic cells, macrophages, and B cells
present antigens.
* *Question 14**
Which cell type is the primary antigen-presenting cell that activates naive T cells?
A. Macrophage
B. B cell
C. Dendritic cell **[CORRECT]**
D. Neutrophil
* *Rationale:** Dendritic cells are the most potent antigen-presenting cells and are uniquely
capable of activating naive T cells. They capture antigens in peripheral tissues and migrate to
N
Complete Solution | Graduate Nursing
| Advanced Practice | Pass Guaranteed
- A+ Graded
**[DOMAIN 1: IMMUNE SYSTEM FUNCTION & DISORDERS - 45 Questions]**
* *Question 1**
Which leukocyte is the most numerous and serves as the first responder during bacterial
infections?
A. Eosinophil
B. Basophil
C. Neutrophil **[CORRECT]**
D. Lymphocyte
* *Rationale:** Neutrophils constitute 50-70% of circulating leukocytes and are the first cells to
arrive at sites of bacterial infection. They are highly phagocytic and contain granules with
antimicrobial substances. Eosinophils primarily respond to parasites and allergic reactions.
Basophils release histamine during allergic responses. Lymphocytes mediate adaptive immunity
but arrive later in the inflammatory response.
* *Question 2**
A patient presents with a WBC count of 3,200/mm³. What condition does this indicate?
A. Neutrophilia
B. Leukopenia **[CORRECT]**
C. Leukocytosis
D. Eosinophilia
* *Rationale:** Leukopenia is defined as a WBC count below 4,000/mm³ (normal range:
5,000-10,000/mm³). This places the patient at increased risk for infections. Neutrophilia refers to
elevated neutrophils. Leukocytosis is elevated total WBC count. Eosinophilia indicates
increased eosinophils, often seen in parasitic infections or allergies.
* *Question 3**
Where do B lymphocytes mature?
A. Thymus
B. Spleen
C. Bone marrow **[CORRECT]**
,D. Lymph nodes
* *Rationale:** B cells mature in the bone marrow (hence "B" for bone marrow). T cells mature in
the thymus. The spleen and lymph nodes are secondary lymphoid organs where immune
responses are initiated, but they are not sites of lymphocyte maturation.
* *Question 4**
Which immunoglobulin is the most abundant in serum and provides passive immunity to the
fetus?
A. IgA
B. IgM
C. IgE
D. IgG **[CORRECT]**
* *Rationale:** IgG comprises approximately 80% of serum immunoglobulins and is the only
antibody class that crosses the placenta, providing passive immunity to the newborn. IgA is
found in secretions. IgM is the first antibody produced in response to infection. IgE is involved in
allergic reactions.
* *Question 5**
Which cells are responsible for killing virus-infected cells and tumor cells without prior
sensitization?
A. B cells
B. Helper T cells
C. Natural Killer (NK) cells **[CORRECT]**
D. Eosinophils
* *Rationale:** NK cells are part of the innate immune system and can recognize and destroy
virus-infected cells and tumor cells without prior exposure or antigen presentation. This
distinguishes them from cytotoxic T cells, which require antigen presentation via MHC Class I
molecules.
* *Question 6**
MHC Class I molecules present antigens to which cells?
A. CD4+ T cells
B. CD8+ T cells **[CORRECT]**
C. B cells
D. Macrophages
* *Rationale:** MHC Class I molecules are expressed on all nucleated cells and present
endogenous antigens (viral peptides, tumor antigens) to CD8+ cytotoxic T cells. MHC Class II
molecules, found on antigen-presenting cells, present exogenous antigens to CD4+ helper T
cells.
,* *Question 7**
Which cell type becomes macrophages when they enter tissues?
A. Neutrophils
B. Monocytes **[CORRECT]**
C. Basophils
D. Lymphocytes
* *Rationale:** Monocytes circulate in blood and differentiate into macrophages upon entering
tissues. Macrophages are highly phagocytic and serve as antigen-presenting cells. Neutrophils
remain as neutrophils. Basophils and lymphocytes do not transform into macrophages.
* *Question 8**
Which lymphoid organ filters blood and removes old erythrocytes?
A. Thymus
B. Lymph nodes
C. Spleen **[CORRECT]**
D. Tonsils
* *Rationale:** The spleen filters blood, removes senescent red blood cells, and serves as a site
for immune activation. Lymph nodes filter lymph. The thymus is a primary lymphoid organ for T
cell maturation. Tonsils are part of MALT (mucosa-associated lymphoid tissue).
* *Question 9**
Which antibody class is found in tears, saliva, and breast milk?
A. IgG
B. IgA **[CORRECT]**
C. IgM
D. IgD
* *Rationale:** IgA is the primary antibody in secretions (tears, saliva, breast milk, respiratory
and GI secretions), providing mucosal immunity. Secretory IgA prevents pathogen attachment to
mucosal surfaces. IgG dominates serum antibodies. IgM is the first response antibody. IgD
functions in B cell activation.
* *Question 10**
Helper T cells express which surface marker?
A. CD8
B. CD4 **[CORRECT]**
C. CD56
D. CD19
* *Rationale:** Helper T cells are CD4+ T cells that recognize antigens presented by MHC Class
II molecules on antigen-presenting cells. CD8 is expressed on cytotoxic T cells. CD56 is an NK
cell marker. CD19 is a B cell marker.
, * *Question 11**
Which immunoglobulin indicates a recent or current infection?
A. IgG
B. IgM **[CORRECT]**
C. IgA
D. IgE
* *Rationale:** IgM is the first antibody produced during a primary immune response, appearing
within 3-5 days of infection. Its presence indicates acute or recent infection. IgG appears later
and persists for long-term immunity. IgA and IgE are not primary indicators of recent infection.
* *Question 12**
Which chemical barrier in the stomach helps prevent infection?
A. Mucus
B. Hydrochloric acid **[CORRECT]**
C. Lysozyme
D. Cilia
* *Rationale:** Gastric hydrochloric acid creates a pH of 1-3, destroying most ingested
pathogens. Mucus is a physical barrier. Lysozyme is found in tears and saliva. Cilia are
mechanical barriers in the respiratory tract.
* *Question 13**
What is the primary function of regulatory T cells (Tregs)?
A. Kill infected cells
B. Produce antibodies
C. Suppress immune responses **[CORRECT]**
D. Present antigens
* *Rationale:** Regulatory T cells (Tregs) suppress immune responses to prevent autoimmunity
and maintain tolerance to self-antigens. They are crucial for immune homeostasis. Cytotoxic T
cells kill infected cells. B cells produce antibodies. Dendritic cells, macrophages, and B cells
present antigens.
* *Question 14**
Which cell type is the primary antigen-presenting cell that activates naive T cells?
A. Macrophage
B. B cell
C. Dendritic cell **[CORRECT]**
D. Neutrophil
* *Rationale:** Dendritic cells are the most potent antigen-presenting cells and are uniquely
capable of activating naive T cells. They capture antigens in peripheral tissues and migrate to
