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 – 100% Correct
1. The primary pacemaker of the heart is the Answer: sinoatrial (SA) nodeRationale: The
SA node, located in the right atrium near the superior vena cava, has the fastest intrinsic
firing rate (60–100 bpm) and initiates each normal cardiac cycle, making it the heart's
primary pacemaker.
2. The P wave on an ECG represents Answer: atrial depolarizationRationale: The P wave
is the first positive deflection on the ECG and corresponds to the spread of depolarization
through the atria, triggering atrial contraction.
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 return to their resting membrane
potential after contraction. It is typically 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 (AV node conduction time).
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 causes pulmonary congestion and pulmonary
hypertension, which increases afterload on the right ventricle, eventually leading to right
ventricular failure (cor pulmonale).
7. According to the Frank-Starling law of the heart Answer: increased preload leads to
increased stroke volumeRationale: Within physiological limits, greater end-diastolic
volume (preload) stretches cardiac muscle fibers, increasing the force of contraction and
stroke volume due to optimal actin-myosin overlap.
8. The hormone primarily responsible for increasing blood calcium levels is Answer:
parathyroid hormone (PTH)Rationale: PTH stimulates osteoclasts to release calcium
from bone, increases renal calcium reabsorption, and promotes activation of vitamin D in
the kidneys, all raising serum calcium.
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 constitutes ~60% of total plasma protein and is
the primary contributor to colloid osmotic (oncotic) pressure, which prevents fluid loss
from capillaries into tissues.
11. The intrinsic pathway of coagulation is initiated by Answer: contact with negatively
charged surfacesRationale: The intrinsic pathway begins when factor XII contacts
exposed collagen or other negatively charged surfaces 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 through factor X.
2027) Anatomy and Physiology II with Lab –
Chamberlain College of Nursing 100 Verified
Questions & 100% Correct Answers with Rationales
Grade A – 100% Correct
1. The primary pacemaker of the heart is the Answer: sinoatrial (SA) nodeRationale: The
SA node, located in the right atrium near the superior vena cava, has the fastest intrinsic
firing rate (60–100 bpm) and initiates each normal cardiac cycle, making it the heart's
primary pacemaker.
2. The P wave on an ECG represents Answer: atrial depolarizationRationale: The P wave
is the first positive deflection on the ECG and corresponds to the spread of depolarization
through the atria, triggering atrial contraction.
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 return to their resting membrane
potential after contraction. It is typically 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 (AV node conduction time).
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 causes pulmonary congestion and pulmonary
hypertension, which increases afterload on the right ventricle, eventually leading to right
ventricular failure (cor pulmonale).
7. According to the Frank-Starling law of the heart Answer: increased preload leads to
increased stroke volumeRationale: Within physiological limits, greater end-diastolic
volume (preload) stretches cardiac muscle fibers, increasing the force of contraction and
stroke volume due to optimal actin-myosin overlap.
8. The hormone primarily responsible for increasing blood calcium levels is Answer:
parathyroid hormone (PTH)Rationale: PTH stimulates osteoclasts to release calcium
from bone, increases renal calcium reabsorption, and promotes activation of vitamin D in
the kidneys, all raising serum calcium.
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 constitutes ~60% of total plasma protein and is
the primary contributor to colloid osmotic (oncotic) pressure, which prevents fluid loss
from capillaries into tissues.
11. The intrinsic pathway of coagulation is initiated by Answer: contact with negatively
charged surfacesRationale: The intrinsic pathway begins when factor XII contacts
exposed collagen or other negatively charged surfaces 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 through factor X.
