Exam 2: BIOS 252 / BIOS252 (Latest Update 2026 /
2027) Anatomy and Physiology II with Lab –
Chamberlain College of Nursing 100 Verified
Questions & 100% Correct Answers with Rationales
Grade A – Current as of 2026/2027
1. The primary pacemaker of the heart is the Answer: sinoatrial (SA) nodeRationale: The
SA node, located in the right atrium near the entrance of the superior vena cava, has the
fastest intrinsic firing rate (60–100 bpm) and initiates each normal cardiac cycle. It is
called the pacemaker because it sets the rhythm for the entire heart.
2. The P wave on an ECG represents Answer: atrial depolarizationRationale: The P wave
is the first positive deflection and corresponds to the spread of depolarization through the
atria, initiating atrial contraction. It precedes the QRS complex.
3. The QRS complex on an ECG represents Answer: ventricular
depolarizationRationale: The QRS complex is the large, sharp deflection that occurs as
the ventricles depolarize rapidly via the Purkinje fibers, immediately followed by
ventricular contraction.
4. The T wave on an ECG represents Answer: ventricular repolarizationRationale: The
T wave occurs as ventricular myocytes repolarize and recover their resting membrane
potential after contraction. It is usually in the same direction as the QRS complex.
5. The normal range for the PR interval on an ECG is Answer: 0.12–0.20
secondsRationale: The PR interval measures the time from the beginning of atrial
depolarization to the beginning of ventricular depolarization (conduction through the AV
node). A PR interval >0.20 seconds indicates first-degree AV block.
, 6. The most common cause of right-sided heart failure is Answer: left-sided heart
failureRationale: Left-sided failure leads to backup of blood into the pulmonary
circulation, causing pulmonary hypertension. This increases afterload on the right
ventricle, eventually leading to right ventricular failure (cor pulmonale).
7. The Frank-Starling law of the heart states that Answer: increased preload leads to
increased stroke volumeRationale: Within physiological limits, the greater the end-
diastolic volume (preload), the greater the force of contraction and stroke volume, due to
optimal overlap of actin and myosin filaments in cardiac muscle.
8. The hormone primarily responsible for increasing blood calcium levels is Answer:
parathyroid hormone (PTH)Rationale: PTH stimulates osteoclast activity to release
calcium from bone, increases renal calcium reabsorption, and promotes activation of
vitamin D in the kidneys, all of which raise serum calcium levels.
9. The primary stimulus for aldosterone secretion is Answer: angiotensin IIRationale:
Angiotensin II directly stimulates the zona glomerulosa of the adrenal cortex to secrete
aldosterone, which increases sodium reabsorption and potassium excretion in the kidneys.
10. The most abundant plasma protein responsible for maintaining oncotic pressure is
Answer: albuminRationale: Albumin accounts for approximately 60% of total plasma
protein and is the main contributor to colloid osmotic (oncotic) pressure, which helps
retain fluid in the vascular space.
11. The intrinsic pathway of coagulation is initiated by Answer: contact with negatively
charged surfacesRationale: The intrinsic pathway begins when factor XII contacts
collagen or other negatively charged surfaces exposed during vascular injury, leading to
sequential activation of factors XI, IX, and X.
12. The extrinsic pathway of coagulation is initiated by Answer: tissue factor (factor
III)Rationale: Tissue factor is released from damaged tissue and forms a complex with
factor VII, rapidly activating the common pathway via factor X.
2027) Anatomy and Physiology II with Lab –
Chamberlain College of Nursing 100 Verified
Questions & 100% Correct Answers with Rationales
Grade A – Current as of 2026/2027
1. The primary pacemaker of the heart is the Answer: sinoatrial (SA) nodeRationale: The
SA node, located in the right atrium near the entrance of the superior vena cava, has the
fastest intrinsic firing rate (60–100 bpm) and initiates each normal cardiac cycle. It is
called the pacemaker because it sets the rhythm for the entire heart.
2. The P wave on an ECG represents Answer: atrial depolarizationRationale: The P wave
is the first positive deflection and corresponds to the spread of depolarization through the
atria, initiating atrial contraction. It precedes the QRS complex.
3. The QRS complex on an ECG represents Answer: ventricular
depolarizationRationale: The QRS complex is the large, sharp deflection that occurs as
the ventricles depolarize rapidly via the Purkinje fibers, immediately followed by
ventricular contraction.
4. The T wave on an ECG represents Answer: ventricular repolarizationRationale: The
T wave occurs as ventricular myocytes repolarize and recover their resting membrane
potential after contraction. It is usually in the same direction as the QRS complex.
5. The normal range for the PR interval on an ECG is Answer: 0.12–0.20
secondsRationale: The PR interval measures the time from the beginning of atrial
depolarization to the beginning of ventricular depolarization (conduction through the AV
node). A PR interval >0.20 seconds indicates first-degree AV block.
, 6. The most common cause of right-sided heart failure is Answer: left-sided heart
failureRationale: Left-sided failure leads to backup of blood into the pulmonary
circulation, causing pulmonary hypertension. This increases afterload on the right
ventricle, eventually leading to right ventricular failure (cor pulmonale).
7. The Frank-Starling law of the heart states that Answer: increased preload leads to
increased stroke volumeRationale: Within physiological limits, the greater the end-
diastolic volume (preload), the greater the force of contraction and stroke volume, due to
optimal overlap of actin and myosin filaments in cardiac muscle.
8. The hormone primarily responsible for increasing blood calcium levels is Answer:
parathyroid hormone (PTH)Rationale: PTH stimulates osteoclast activity to release
calcium from bone, increases renal calcium reabsorption, and promotes activation of
vitamin D in the kidneys, all of which raise serum calcium levels.
9. The primary stimulus for aldosterone secretion is Answer: angiotensin IIRationale:
Angiotensin II directly stimulates the zona glomerulosa of the adrenal cortex to secrete
aldosterone, which increases sodium reabsorption and potassium excretion in the kidneys.
10. The most abundant plasma protein responsible for maintaining oncotic pressure is
Answer: albuminRationale: Albumin accounts for approximately 60% of total plasma
protein and is the main contributor to colloid osmotic (oncotic) pressure, which helps
retain fluid in the vascular space.
11. The intrinsic pathway of coagulation is initiated by Answer: contact with negatively
charged surfacesRationale: The intrinsic pathway begins when factor XII contacts
collagen or other negatively charged surfaces exposed during vascular injury, leading to
sequential activation of factors XI, IX, and X.
12. The extrinsic pathway of coagulation is initiated by Answer: tissue factor (factor
III)Rationale: Tissue factor is released from damaged tissue and forms a complex with
factor VII, rapidly activating the common pathway via factor X.
