NR 507 WEEK 4 MIDTERM EXAM (PDF) | 2026 QUESTIONS
AND ANSWERS + RATIONALES | STUDY GUIDE | 100%
CORRECT
1. The coronary ostia are located in which anatomical structure?
A) Left ventricle
B) Aortic valve
C) Coronary sinus
D) Aorta
Correct Answer: D) Aorta
Rationale: The coronary ostia are the openings of the coronary arteries, and they are situated in
the aorta just above the aortic valve cusps. This location allows for coronary artery perfusion
during diastole. The left ventricle, aortic valve, and coronary sinus are not the sites of the ostia.
2. Where in the respiratory tract do the majority of foreign objects aspirated by children finally
lodge?
A) Trachea
B) Left lung
C) Bronchus
D) Bronchioles
Correct Answer: C) Bronchus
Rationale: Approximately 75% of aspirated foreign bodies lodge in a bronchus, with the right
main bronchus being the most common site due to its more vertical and wider anatomy. Lodging
in the trachea, left lung, or bronchioles is less frequent in children.
3. Which type of antibody is involved in a Type I hypersensitivity reaction?
A) IgA
B) IgE
C) IgG
D) IgM
Correct Answer: B) IgE
Rationale: Type I hypersensitivity reactions, such as anaphylaxis and allergic asthma, are
mediated by IgE antibodies. These antibodies bind to mast cells and basophils, triggering the
release of histamine and other mediators. IgA, IgG, and IgM are involved in other types of
hypersensitivity.
4. Hypersensitivity is best defined as which of the following?
A) A disturbance in the immunologic tolerance of self-antigens
B) An immunologic reaction of one person to the tissue of another person
, C) An altered immunologic response to an antigen that results in disease
D) An undetectable immune response in the presence of antigens
Correct Answer: C) An altered immunologic response to an antigen that results in disease
Rationale: Hypersensitivity is a state of altered immunologic reactivity that causes tissue damage
or disease when an individual is exposed to an antigen. This is distinct from a normal, protective
immune response. The other options describe autoimmunity, alloimmunity, and immune
deficiency.
5. What is the final stage of the infectious process?
A) Colonization
B) Invasion
C) Multiplication
D) Spread
Correct Answer: D) Spread
Rationale: The infectious process follows a progression: colonization, invasion, multiplication,
and finally spread. Spread allows the infectious organism to move to other tissues or organs,
potentially causing systemic disease. Colonization is the initial establishment, and invasion is the
penetration of host tissues.
6. A researcher is studying apoptosis. Which characteristic finding would confirm that cell death is
occurring via apoptosis rather than necrosis?
A) Swelling and rupture of the plasma membrane
B) A significant inflammatory response in the surrounding tissue
C) Fragmentation of the cell into membrane-bound bodies
D) Release of intracellular enzymes into the bloodstream
Correct Answer: C) Fragmentation of the cell into membrane-bound bodies
Rationale: Apoptosis is a programmed and regulated form of cell death characterized by cell
shrinkage, chromatin condensation, and fragmentation into membrane-bound apoptotic bodies.
This process is orderly and does not trigger an inflammatory response. Necrosis, in contrast,
involves cell swelling, membrane rupture, and inflammation.
7. Which statement concerning benign tumors is true?
A) The resulting pain is severe
B) Benign tumors are not encapsulated
C) Benign tumors are fast growing
D) The cells are well-differentiated
Correct Answer: D) The cells are well-differentiated
, Rationale: A key characteristic of benign tumors is that the cells are well-differentiated, meaning
they closely resemble the tissue of origin. They are typically slow-growing, encapsulated, and
rarely cause severe pain unless they compress surrounding structures.
8. Which complex (wave) represents the sum of all ventricular muscle cell depolarizations?
A) PRS
B) QRS
C) QT interval
D) P wave
Correct Answer: B) QRS
Rationale: The QRS complex on an electrocardiogram (ECG) represents the sum of all
ventricular muscle cell depolarizations. This electrical activity triggers ventricular contraction.
The P wave represents atrial depolarization, and the QT interval encompasses both ventricular
depolarization and repolarization.
9. Which organism is a common sexually transmitted bacterial infection?
A) Staphylococcus aureus
B) Clostridium perfringens
C) Helicobacter pylori
D) Treponema pallidum
Correct Answer: D) Treponema pallidum
Rationale: Treponema pallidum is the spirochete bacterium that causes syphilis, a common
sexually transmitted infection. Staphylococcus aureus causes skin and wound infections,
Clostridium perfringens causes gas gangrene, and Helicobacter pylori causes peptic ulcer
disease.
10. Which organ is stimulated during the alarm phase of the general adaptation syndrome (GAS)?
A) Adrenal cortex
B) Hypothalamus
C) Anterior pituitary
D) Limbic system
Correct Answer: B) Hypothalamus
Rationale: The general adaptation syndrome describes the body's response to stress. The
hypothalamus is the primary organ stimulated during the alarm phase, triggering the sympathetic
nervous system and the HPA axis. This leads to the release of cortisol and catecholamines from
the adrenal glands.
11. Which term refers to an increase in cell size leading to organ enlargement?
A) Hyperplasia
B) Hypertrophy
AND ANSWERS + RATIONALES | STUDY GUIDE | 100%
CORRECT
1. The coronary ostia are located in which anatomical structure?
A) Left ventricle
B) Aortic valve
C) Coronary sinus
D) Aorta
Correct Answer: D) Aorta
Rationale: The coronary ostia are the openings of the coronary arteries, and they are situated in
the aorta just above the aortic valve cusps. This location allows for coronary artery perfusion
during diastole. The left ventricle, aortic valve, and coronary sinus are not the sites of the ostia.
2. Where in the respiratory tract do the majority of foreign objects aspirated by children finally
lodge?
A) Trachea
B) Left lung
C) Bronchus
D) Bronchioles
Correct Answer: C) Bronchus
Rationale: Approximately 75% of aspirated foreign bodies lodge in a bronchus, with the right
main bronchus being the most common site due to its more vertical and wider anatomy. Lodging
in the trachea, left lung, or bronchioles is less frequent in children.
3. Which type of antibody is involved in a Type I hypersensitivity reaction?
A) IgA
B) IgE
C) IgG
D) IgM
Correct Answer: B) IgE
Rationale: Type I hypersensitivity reactions, such as anaphylaxis and allergic asthma, are
mediated by IgE antibodies. These antibodies bind to mast cells and basophils, triggering the
release of histamine and other mediators. IgA, IgG, and IgM are involved in other types of
hypersensitivity.
4. Hypersensitivity is best defined as which of the following?
A) A disturbance in the immunologic tolerance of self-antigens
B) An immunologic reaction of one person to the tissue of another person
, C) An altered immunologic response to an antigen that results in disease
D) An undetectable immune response in the presence of antigens
Correct Answer: C) An altered immunologic response to an antigen that results in disease
Rationale: Hypersensitivity is a state of altered immunologic reactivity that causes tissue damage
or disease when an individual is exposed to an antigen. This is distinct from a normal, protective
immune response. The other options describe autoimmunity, alloimmunity, and immune
deficiency.
5. What is the final stage of the infectious process?
A) Colonization
B) Invasion
C) Multiplication
D) Spread
Correct Answer: D) Spread
Rationale: The infectious process follows a progression: colonization, invasion, multiplication,
and finally spread. Spread allows the infectious organism to move to other tissues or organs,
potentially causing systemic disease. Colonization is the initial establishment, and invasion is the
penetration of host tissues.
6. A researcher is studying apoptosis. Which characteristic finding would confirm that cell death is
occurring via apoptosis rather than necrosis?
A) Swelling and rupture of the plasma membrane
B) A significant inflammatory response in the surrounding tissue
C) Fragmentation of the cell into membrane-bound bodies
D) Release of intracellular enzymes into the bloodstream
Correct Answer: C) Fragmentation of the cell into membrane-bound bodies
Rationale: Apoptosis is a programmed and regulated form of cell death characterized by cell
shrinkage, chromatin condensation, and fragmentation into membrane-bound apoptotic bodies.
This process is orderly and does not trigger an inflammatory response. Necrosis, in contrast,
involves cell swelling, membrane rupture, and inflammation.
7. Which statement concerning benign tumors is true?
A) The resulting pain is severe
B) Benign tumors are not encapsulated
C) Benign tumors are fast growing
D) The cells are well-differentiated
Correct Answer: D) The cells are well-differentiated
, Rationale: A key characteristic of benign tumors is that the cells are well-differentiated, meaning
they closely resemble the tissue of origin. They are typically slow-growing, encapsulated, and
rarely cause severe pain unless they compress surrounding structures.
8. Which complex (wave) represents the sum of all ventricular muscle cell depolarizations?
A) PRS
B) QRS
C) QT interval
D) P wave
Correct Answer: B) QRS
Rationale: The QRS complex on an electrocardiogram (ECG) represents the sum of all
ventricular muscle cell depolarizations. This electrical activity triggers ventricular contraction.
The P wave represents atrial depolarization, and the QT interval encompasses both ventricular
depolarization and repolarization.
9. Which organism is a common sexually transmitted bacterial infection?
A) Staphylococcus aureus
B) Clostridium perfringens
C) Helicobacter pylori
D) Treponema pallidum
Correct Answer: D) Treponema pallidum
Rationale: Treponema pallidum is the spirochete bacterium that causes syphilis, a common
sexually transmitted infection. Staphylococcus aureus causes skin and wound infections,
Clostridium perfringens causes gas gangrene, and Helicobacter pylori causes peptic ulcer
disease.
10. Which organ is stimulated during the alarm phase of the general adaptation syndrome (GAS)?
A) Adrenal cortex
B) Hypothalamus
C) Anterior pituitary
D) Limbic system
Correct Answer: B) Hypothalamus
Rationale: The general adaptation syndrome describes the body's response to stress. The
hypothalamus is the primary organ stimulated during the alarm phase, triggering the sympathetic
nervous system and the HPA axis. This leads to the release of cortisol and catecholamines from
the adrenal glands.
11. Which term refers to an increase in cell size leading to organ enlargement?
A) Hyperplasia
B) Hypertrophy
