SCI 221 Final Exam V3 | SCI 221 Human
Physiology with Intervention Skill-Based
(ISB) Experiential Learning | Q&A with
Rationale (SCI221 Final Exam) |
Nightingale College
1. A patient is experiencing a high fever. Which homeostatic mechanism is primarily
responsible for returning the body temperature to its set point?
A. Negative feedback loop
B. Positive feedback loop
C. Feed-forward regulation
D. Anticipatory response
Correct Answer: A
Rationale: Negative feedback loops are the primary mechanism used by the body to
maintain homeostasis by reversing a deviation from the set point. In the case of a fever, the
body initiates cooling mechanisms like sweating and vasodilation to lower the
temperature. Positive feedback would instead amplify the change, which is typically not
homeostatic for temperature regulation.
2. During the depolarization phase of an action potential, which of the following events
occurs?
A. Potassium ions exit the cell
,B. Chloride ions enter the cell
C. The sodium-potassium pump stops working
D. Sodium ions enter the cell
Correct Answer: D
Rationale: Depolarization is characterized by a rapid influx of sodium ions into the neuron
through voltage-gated channels. This movement of positive charge makes the interior of
the cell less negative relative to the outside. Potassium exit occurs later during the
repolarization phase to restore the resting membrane potential.
3. Which hormone is secreted by the alpha cells of the pancreas to increase blood glucose
levels?
A. Insulin
B. Somatostatin
C. Cortisol
D. Glucagon
Correct Answer: D
Rationale: Glucagon is produced by alpha cells in the pancreatic islets and acts to elevate
blood glucose by stimulating glycogenolysis and gluconeogenesis in the liver. Insulin, by
contrast, is produced by beta cells and lowers blood glucose. Somatostatin inhibits both,
while cortisol is an adrenal hormone that also raises glucose but via different pathways.
,4. In the sliding filament theory of muscle contraction, what is the specific role of calcium
ions?
A. To bind to myosin heads to activate them
B. To bind to tropomyosin to reveal binding sites
C. To bind to troponin, causing a conformational change in tropomyosin
D. To provide energy for the power stroke
Correct Answer: C
Rationale: Calcium ions released from the sarcoplasmic reticulum bind to troponin on the
thin filaments. This binding causes troponin to change shape, which pulls tropomyosin
away from the myosin-binding sites on actin. Once these sites are exposed, the myosin
heads can bind to actin to initiate contraction.
5. Which of the following describes the correct path of blood flow through the heart, starting
from the vena cava?
A. Right atrium, mitral valve, right ventricle, pulmonary artery
B. Left atrium, bicuspid valve, left ventricle, aortic valve
C. Right atrium, tricuspid valve, right ventricle, pulmonary valve
D. Right ventricle, tricuspid valve, right atrium, pulmonary vein
Correct Answer: C
, Rationale: Deoxygenated blood enters the right atrium from the vena cavae and passes
through the tricuspid valve into the right ventricle. From the right ventricle, it is pumped
through the pulmonary semilunar valve into the pulmonary trunk toward the lungs. The
mitral (bicuspid) valve is located on the left side of the heart between the left atrium and
ventricle.
6. What occurs during the P-wave of a normal electrocardiogram (ECG)?
A. Ventricular depolarization
B. Atrial depolarization
C. Atrial repolarization
D. Ventricular repolarization
Correct Answer: B
Rationale: The P-wave represents the electrical impulse spreading from the SA node
through the atria, known as atrial depolarization. This electrical event precedes the
mechanical contraction of the atria. Ventricular depolarization is represented by the QRS
complex, and ventricular repolarization is represented by the T-wave.
7. Which factor would cause the oxyhemoglobin dissociation curve to shift to the right,
facilitating the unloading of oxygen to tissues?
A. Decreased temperature
B. Increased pH (alkalosis)
C. Increased partial pressure of carbon dioxide (PCO2)
Physiology with Intervention Skill-Based
(ISB) Experiential Learning | Q&A with
Rationale (SCI221 Final Exam) |
Nightingale College
1. A patient is experiencing a high fever. Which homeostatic mechanism is primarily
responsible for returning the body temperature to its set point?
A. Negative feedback loop
B. Positive feedback loop
C. Feed-forward regulation
D. Anticipatory response
Correct Answer: A
Rationale: Negative feedback loops are the primary mechanism used by the body to
maintain homeostasis by reversing a deviation from the set point. In the case of a fever, the
body initiates cooling mechanisms like sweating and vasodilation to lower the
temperature. Positive feedback would instead amplify the change, which is typically not
homeostatic for temperature regulation.
2. During the depolarization phase of an action potential, which of the following events
occurs?
A. Potassium ions exit the cell
,B. Chloride ions enter the cell
C. The sodium-potassium pump stops working
D. Sodium ions enter the cell
Correct Answer: D
Rationale: Depolarization is characterized by a rapid influx of sodium ions into the neuron
through voltage-gated channels. This movement of positive charge makes the interior of
the cell less negative relative to the outside. Potassium exit occurs later during the
repolarization phase to restore the resting membrane potential.
3. Which hormone is secreted by the alpha cells of the pancreas to increase blood glucose
levels?
A. Insulin
B. Somatostatin
C. Cortisol
D. Glucagon
Correct Answer: D
Rationale: Glucagon is produced by alpha cells in the pancreatic islets and acts to elevate
blood glucose by stimulating glycogenolysis and gluconeogenesis in the liver. Insulin, by
contrast, is produced by beta cells and lowers blood glucose. Somatostatin inhibits both,
while cortisol is an adrenal hormone that also raises glucose but via different pathways.
,4. In the sliding filament theory of muscle contraction, what is the specific role of calcium
ions?
A. To bind to myosin heads to activate them
B. To bind to tropomyosin to reveal binding sites
C. To bind to troponin, causing a conformational change in tropomyosin
D. To provide energy for the power stroke
Correct Answer: C
Rationale: Calcium ions released from the sarcoplasmic reticulum bind to troponin on the
thin filaments. This binding causes troponin to change shape, which pulls tropomyosin
away from the myosin-binding sites on actin. Once these sites are exposed, the myosin
heads can bind to actin to initiate contraction.
5. Which of the following describes the correct path of blood flow through the heart, starting
from the vena cava?
A. Right atrium, mitral valve, right ventricle, pulmonary artery
B. Left atrium, bicuspid valve, left ventricle, aortic valve
C. Right atrium, tricuspid valve, right ventricle, pulmonary valve
D. Right ventricle, tricuspid valve, right atrium, pulmonary vein
Correct Answer: C
, Rationale: Deoxygenated blood enters the right atrium from the vena cavae and passes
through the tricuspid valve into the right ventricle. From the right ventricle, it is pumped
through the pulmonary semilunar valve into the pulmonary trunk toward the lungs. The
mitral (bicuspid) valve is located on the left side of the heart between the left atrium and
ventricle.
6. What occurs during the P-wave of a normal electrocardiogram (ECG)?
A. Ventricular depolarization
B. Atrial depolarization
C. Atrial repolarization
D. Ventricular repolarization
Correct Answer: B
Rationale: The P-wave represents the electrical impulse spreading from the SA node
through the atria, known as atrial depolarization. This electrical event precedes the
mechanical contraction of the atria. Ventricular depolarization is represented by the QRS
complex, and ventricular repolarization is represented by the T-wave.
7. Which factor would cause the oxyhemoglobin dissociation curve to shift to the right,
facilitating the unloading of oxygen to tissues?
A. Decreased temperature
B. Increased pH (alkalosis)
C. Increased partial pressure of carbon dioxide (PCO2)
