BIOS 255 Midterm Exam Questions and Answers with
Rationales |
CHAMBERLAIN UNIVERSITY
Question 1. Which mechanism best explains the normal physiology of diastolic arterial pressure?
A. elastic recoil and peripheral resistance maintain arterial pressure while the ventricle relaxes
B. increased stretch raises afferent signaling and tends to reduce sympathetic drive while increasing
parasympathetic influence
C. the pressure gradient favors filtration, especially toward the arterial side of many capillary beds
D. left ventricular ejection raises arterial volume and pressure to a maximum before pressure declines
Correct Answer: A. elastic recoil and peripheral resistance maintain arterial pressure while the ventricle relaxes
Explanation: The correct mechanism is that elastic recoil and peripheral resistance maintain arterial pressure while the
ventricle relaxes. It explains the normal function of diastolic arterial pressure: is the lowest major arterial pressure during
ventricular diastole before the next systolic rise. The other mechanisms belong to different structures or processes in the
same broad system.
Question 2. A vessel supplying the left ventricular myocardium is abruptly occluded. Which explanation
best accounts for this finding?
A. the QRS complex reflects ventricular depolarization
B. loss of coronary arterial flow deprives cardiac muscle of oxygen
C. the sinoatrial node normally has the highest intrinsic firing rate
D. the His-Purkinje network normally provides rapid ventricular conduction
Correct Answer: B. loss of coronary arterial flow deprives cardiac muscle of oxygen
Explanation: The best interpretation is that loss of coronary arterial flow deprives cardiac muscle of oxygen. This
scenario centers on coronary arteries, whose normal physiologic role is described as follows: deliver oxygenated blood
to the myocardium so cardiac muscle can sustain continuous work. That relationship is more directly supported by the
stated findings than the alternative explanations.
Question 3. A learner notes the following feature: it is a dilated saclike structure in the upper abdomen.
Which structure or process is being described?
A. cisterna chyli
B. lymphatic capillary
C. afferent lymphatic vessel
D. thoracic duct
Correct Answer: A. cisterna chyli
Explanation: The description identifies cisterna chyli because it is a dilated saclike structure in the upper abdomen. Its
key role is that it serves as an enlarged lymphatic reservoir that receives intestinal and lumbar lymph before continuing
as the thoracic duct. The alternative options have different defining features and would not best fit the description.
Question 4. A patient scenario shows the following: A person has a heart rate of 75 beats per minute and
a stroke volume of 70 mL per beat. Which interpretation is most accurate?
A. cardiac output is 5.25 L per minute because heart rate is multiplied by stroke volume
B. cardiac output is 0.93 L per minute because stroke volume is divided by heart rate
C. cardiac output is 10.5 L per minute because the one-ventricle result is incorrectly doubled
D. cardiac output is 145 mL per minute because heart rate and stroke volume are incorrectly added
Correct Answer: A. cardiac output is 5.25 L per minute because heart rate is multiplied by stroke volume
,Explanation: The best interpretation is that cardiac output is 5.25 L per minute because heart rate is multiplied by stroke
volume. This scenario centers on cardiac output, whose normal physiologic role is described as follows: expresses the
volume of blood pumped by one ventricle per minute. That relationship is more directly supported by the stated findings
than the alternative explanations.
Question 5. A student is distinguishing closely related structures and processes. Which finding best
identifies intestinal lacteal?
A. it is lymphoid tissue arranged around branches of the splenic arterial circulation
B. numerous valves divide collecting vessels into short functional segments
C. it is a specialized lymphatic capillary located within an intestinal villus
D. it produces localized lymphedema downstream from blocked or removed lymphatic pathways
Correct Answer: C. it is a specialized lymphatic capillary located within an intestinal villus
Explanation: The identifying feature is that it is a specialized lymphatic capillary located within an intestinal villus. That
characteristic is consistent with intestinal lacteal and its normal role: absorbs dietary lipids from the small intestine into
lymph. The other findings are characteristic of different items and do not identify intestinal lacteal as precisely.
Question 6. After right ventricular ejection, blood briefly tends to move back toward the ventricle.
Which explanation best accounts for this finding?
A. incompetence of the tricuspid valve allows this regurgitant flow
B. the defective valve is the mitral valve
C. closure of the pulmonary semilunar valve prevents that backflow
D. aortic valve closure prevents retrograde aortic flow into the ventricle
Correct Answer: C. closure of the pulmonary semilunar valve prevents that backflow
Explanation: The best interpretation is that closure of the pulmonary semilunar valve prevents that backflow. This
scenario centers on pulmonary semilunar valve, whose normal physiologic role is described as follows: prevents blood
in the pulmonary trunk from returning to the right ventricle during ventricular diastole. That relationship is more directly
supported by the stated findings than the alternative explanations.
Question 7. Which combination correctly matches neutrophil with an identifying feature and a likely
consequence of severe dysfunction?
A. Feature: it is typically the largest leukocyte in a blood smear and has a kidney-shaped nucleus / Dysfunction:
early defense against many bacterial infections would be weakened.
B. Feature: it is the most abundant circulating leukocyte and has a multilobed nucleus with pale granules /
Dysfunction: early defense against many bacterial infections would be weakened.
C. Feature: it is a granulocyte with a bilobed nucleus and prominent red-orange granules / Dysfunction: early
defense against many bacterial infections would be weakened.
D. Feature: it is a rare circulating granulocyte whose dark granules may obscure its bilobed nucleus / Dysfunction:
early defense against many bacterial infections would be weakened.
Correct Answer: B. Feature: it is the most abundant circulating leukocyte and has a multilobed nucleus with pale
granules / Dysfunction: early defense against many bacterial infections would be weakened.
Explanation: For neutrophil, the identifying feature is that it is the most abundant circulating leukocyte and has a
multilobed nucleus with pale granules, and severe dysfunction would mean that early defense against many bacterial
infections would be weakened. Both halves of the pairing must be correct for the option to be valid. The distractors
combine the correct consequence with a defining feature that belongs to another item.
, Question 8. Which feature is most characteristic of plasma colloid osmotic pressure?
A. it is the blood pressure acting against the inside of the capillary wall
B. small changes in arteriolar radius produce disproportionately large changes in resistance
C. it can follow major hemorrhage or severe fluid loss
D. it depends strongly on plasma protein concentration, especially albumin
Correct Answer: D. it depends strongly on plasma protein concentration, especially albumin
Explanation: The identifying feature is that it depends strongly on plasma protein concentration, especially albumin.
That characteristic is consistent with plasma colloid osmotic pressure and its normal role: pulls water into capillaries
because plasma proteins are largely retained within the vascular compartment. The other findings are characteristic of
different items and do not identify plasma colloid osmotic pressure as precisely.
Question 9. Which pairing correctly links sympathetic cardiac stimulation with its function and
mechanism?
A. It raises heart rate and contractility to support increased cardiac output during stress or exercise; this is enabled
because ventricular filling, contractility, and afterload influence the amount ejected with each beat.
B. It raises heart rate and contractility to support increased cardiac output during stress or exercise; this is enabled
because changes in either heart rate or stroke volume alter minute-to-minute systemic blood flow.
C. It raises heart rate and contractility to support increased cardiac output during stress or exercise; this is enabled
because increased pacemaker activity and calcium handling accelerate rate and strengthen contraction.
D. It raises heart rate and contractility to support increased cardiac output during stress or exercise; this is enabled
because increased preload stretches ventricular fibers, improving cross-bridge interaction and contraction strength.
Correct Answer: C. It raises heart rate and contractility to support increased cardiac output during stress or
exercise; this is enabled because increased pacemaker activity and calcium handling accelerate rate and
strengthen contraction.
Explanation: The correct pairing links sympathetic cardiac stimulation to this role: raises heart rate and contractility to
support increased cardiac output during stress or exercise, and to this mechanism: increased pacemaker activity and
calcium handling accelerate rate and strengthen contraction. A correct function paired with the wrong mechanism is still
an incorrect description. The other options deliberately mix the role of sympathetic cardiac stimulation with mechanisms
that belong to different components.
Question 10. Which observation most strongly supports identifying venule?
A. small venules have thin walls and postcapillary venules are important sites of leukocyte exit from blood
B. it consists of folds of the tunica intima oriented to permit one-way flow toward the heart
C. it has a small lumen surrounded by one or more layers of smooth muscle
D. its tunica media contains a relatively high proportion of smooth muscle
Correct Answer: A. small venules have thin walls and postcapillary venules are important sites of leukocyte exit
from blood
Explanation: The identifying feature is that small venules have thin walls and postcapillary venules are important sites of
leukocyte exit from blood. That characteristic is consistent with venule and its normal role: collects blood from capillary
beds and begins returning it toward larger veins. The other findings are characteristic of different items and do not
identify venule as precisely.
Rationales |
CHAMBERLAIN UNIVERSITY
Question 1. Which mechanism best explains the normal physiology of diastolic arterial pressure?
A. elastic recoil and peripheral resistance maintain arterial pressure while the ventricle relaxes
B. increased stretch raises afferent signaling and tends to reduce sympathetic drive while increasing
parasympathetic influence
C. the pressure gradient favors filtration, especially toward the arterial side of many capillary beds
D. left ventricular ejection raises arterial volume and pressure to a maximum before pressure declines
Correct Answer: A. elastic recoil and peripheral resistance maintain arterial pressure while the ventricle relaxes
Explanation: The correct mechanism is that elastic recoil and peripheral resistance maintain arterial pressure while the
ventricle relaxes. It explains the normal function of diastolic arterial pressure: is the lowest major arterial pressure during
ventricular diastole before the next systolic rise. The other mechanisms belong to different structures or processes in the
same broad system.
Question 2. A vessel supplying the left ventricular myocardium is abruptly occluded. Which explanation
best accounts for this finding?
A. the QRS complex reflects ventricular depolarization
B. loss of coronary arterial flow deprives cardiac muscle of oxygen
C. the sinoatrial node normally has the highest intrinsic firing rate
D. the His-Purkinje network normally provides rapid ventricular conduction
Correct Answer: B. loss of coronary arterial flow deprives cardiac muscle of oxygen
Explanation: The best interpretation is that loss of coronary arterial flow deprives cardiac muscle of oxygen. This
scenario centers on coronary arteries, whose normal physiologic role is described as follows: deliver oxygenated blood
to the myocardium so cardiac muscle can sustain continuous work. That relationship is more directly supported by the
stated findings than the alternative explanations.
Question 3. A learner notes the following feature: it is a dilated saclike structure in the upper abdomen.
Which structure or process is being described?
A. cisterna chyli
B. lymphatic capillary
C. afferent lymphatic vessel
D. thoracic duct
Correct Answer: A. cisterna chyli
Explanation: The description identifies cisterna chyli because it is a dilated saclike structure in the upper abdomen. Its
key role is that it serves as an enlarged lymphatic reservoir that receives intestinal and lumbar lymph before continuing
as the thoracic duct. The alternative options have different defining features and would not best fit the description.
Question 4. A patient scenario shows the following: A person has a heart rate of 75 beats per minute and
a stroke volume of 70 mL per beat. Which interpretation is most accurate?
A. cardiac output is 5.25 L per minute because heart rate is multiplied by stroke volume
B. cardiac output is 0.93 L per minute because stroke volume is divided by heart rate
C. cardiac output is 10.5 L per minute because the one-ventricle result is incorrectly doubled
D. cardiac output is 145 mL per minute because heart rate and stroke volume are incorrectly added
Correct Answer: A. cardiac output is 5.25 L per minute because heart rate is multiplied by stroke volume
,Explanation: The best interpretation is that cardiac output is 5.25 L per minute because heart rate is multiplied by stroke
volume. This scenario centers on cardiac output, whose normal physiologic role is described as follows: expresses the
volume of blood pumped by one ventricle per minute. That relationship is more directly supported by the stated findings
than the alternative explanations.
Question 5. A student is distinguishing closely related structures and processes. Which finding best
identifies intestinal lacteal?
A. it is lymphoid tissue arranged around branches of the splenic arterial circulation
B. numerous valves divide collecting vessels into short functional segments
C. it is a specialized lymphatic capillary located within an intestinal villus
D. it produces localized lymphedema downstream from blocked or removed lymphatic pathways
Correct Answer: C. it is a specialized lymphatic capillary located within an intestinal villus
Explanation: The identifying feature is that it is a specialized lymphatic capillary located within an intestinal villus. That
characteristic is consistent with intestinal lacteal and its normal role: absorbs dietary lipids from the small intestine into
lymph. The other findings are characteristic of different items and do not identify intestinal lacteal as precisely.
Question 6. After right ventricular ejection, blood briefly tends to move back toward the ventricle.
Which explanation best accounts for this finding?
A. incompetence of the tricuspid valve allows this regurgitant flow
B. the defective valve is the mitral valve
C. closure of the pulmonary semilunar valve prevents that backflow
D. aortic valve closure prevents retrograde aortic flow into the ventricle
Correct Answer: C. closure of the pulmonary semilunar valve prevents that backflow
Explanation: The best interpretation is that closure of the pulmonary semilunar valve prevents that backflow. This
scenario centers on pulmonary semilunar valve, whose normal physiologic role is described as follows: prevents blood
in the pulmonary trunk from returning to the right ventricle during ventricular diastole. That relationship is more directly
supported by the stated findings than the alternative explanations.
Question 7. Which combination correctly matches neutrophil with an identifying feature and a likely
consequence of severe dysfunction?
A. Feature: it is typically the largest leukocyte in a blood smear and has a kidney-shaped nucleus / Dysfunction:
early defense against many bacterial infections would be weakened.
B. Feature: it is the most abundant circulating leukocyte and has a multilobed nucleus with pale granules /
Dysfunction: early defense against many bacterial infections would be weakened.
C. Feature: it is a granulocyte with a bilobed nucleus and prominent red-orange granules / Dysfunction: early
defense against many bacterial infections would be weakened.
D. Feature: it is a rare circulating granulocyte whose dark granules may obscure its bilobed nucleus / Dysfunction:
early defense against many bacterial infections would be weakened.
Correct Answer: B. Feature: it is the most abundant circulating leukocyte and has a multilobed nucleus with pale
granules / Dysfunction: early defense against many bacterial infections would be weakened.
Explanation: For neutrophil, the identifying feature is that it is the most abundant circulating leukocyte and has a
multilobed nucleus with pale granules, and severe dysfunction would mean that early defense against many bacterial
infections would be weakened. Both halves of the pairing must be correct for the option to be valid. The distractors
combine the correct consequence with a defining feature that belongs to another item.
, Question 8. Which feature is most characteristic of plasma colloid osmotic pressure?
A. it is the blood pressure acting against the inside of the capillary wall
B. small changes in arteriolar radius produce disproportionately large changes in resistance
C. it can follow major hemorrhage or severe fluid loss
D. it depends strongly on plasma protein concentration, especially albumin
Correct Answer: D. it depends strongly on plasma protein concentration, especially albumin
Explanation: The identifying feature is that it depends strongly on plasma protein concentration, especially albumin.
That characteristic is consistent with plasma colloid osmotic pressure and its normal role: pulls water into capillaries
because plasma proteins are largely retained within the vascular compartment. The other findings are characteristic of
different items and do not identify plasma colloid osmotic pressure as precisely.
Question 9. Which pairing correctly links sympathetic cardiac stimulation with its function and
mechanism?
A. It raises heart rate and contractility to support increased cardiac output during stress or exercise; this is enabled
because ventricular filling, contractility, and afterload influence the amount ejected with each beat.
B. It raises heart rate and contractility to support increased cardiac output during stress or exercise; this is enabled
because changes in either heart rate or stroke volume alter minute-to-minute systemic blood flow.
C. It raises heart rate and contractility to support increased cardiac output during stress or exercise; this is enabled
because increased pacemaker activity and calcium handling accelerate rate and strengthen contraction.
D. It raises heart rate and contractility to support increased cardiac output during stress or exercise; this is enabled
because increased preload stretches ventricular fibers, improving cross-bridge interaction and contraction strength.
Correct Answer: C. It raises heart rate and contractility to support increased cardiac output during stress or
exercise; this is enabled because increased pacemaker activity and calcium handling accelerate rate and
strengthen contraction.
Explanation: The correct pairing links sympathetic cardiac stimulation to this role: raises heart rate and contractility to
support increased cardiac output during stress or exercise, and to this mechanism: increased pacemaker activity and
calcium handling accelerate rate and strengthen contraction. A correct function paired with the wrong mechanism is still
an incorrect description. The other options deliberately mix the role of sympathetic cardiac stimulation with mechanisms
that belong to different components.
Question 10. Which observation most strongly supports identifying venule?
A. small venules have thin walls and postcapillary venules are important sites of leukocyte exit from blood
B. it consists of folds of the tunica intima oriented to permit one-way flow toward the heart
C. it has a small lumen surrounded by one or more layers of smooth muscle
D. its tunica media contains a relatively high proportion of smooth muscle
Correct Answer: A. small venules have thin walls and postcapillary venules are important sites of leukocyte exit
from blood
Explanation: The identifying feature is that small venules have thin walls and postcapillary venules are important sites of
leukocyte exit from blood. That characteristic is consistent with venule and its normal role: collects blood from capillary
beds and begins returning it toward larger veins. The other findings are characteristic of different items and do not
identify venule as precisely.
