BIOS 255 / BIOS255 EXAM 1 (2024/ 2025 Update) Anatomy and
Physiology III Complete Guide | 100% Correct| Grade A -Chamberlain
Question 1
Which hormone is released by the beta cells of the pancreas in response to high blood glucose
levels?
A) Glucagon
B) Somatostatin
C) Insulin
D) Cortisol
E) Gastrin
Correct Answer: C) Insulin
Rationale: The beta cells of the pancreatic islets are responsible for synthesizing and
secreting insulin. Insulin is an anabolic hormone that is released when blood glucose levels
are elevated, such as after a meal. It promotes the uptake, utilization, and storage of
glucose by body cells, particularly liver, muscle, and adipose tissue, thereby lowering blood
glucose levels.
Question 2
A client is diagnosed with a tumor in the posterior pituitary gland. The nurse would anticipate
that the secretion of which two hormones would be affected?
A) Growth Hormone (GH) and Prolactin (PRL)
B) Thyroid-Stimulating Hormone (TSH) and Adrenocorticotropic Hormone (ACTH)
C) Antidiuretic Hormone (ADH) and Oxytocin (OT)
D) Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH)
E) Melatonin and Calcitonin
Correct Answer: C) Antidiuretic Hormone (ADH) and Oxytocin (OT)
Rationale: The posterior pituitary does not produce hormones but rather stores and releases
two hormones that are produced in the hypothalamus: antidiuretic hormone (ADH) and
oxytocin. ADH is crucial for water reabsorption in the kidneys, and oxytocin is involved in
uterine contractions and milk ejection. A tumor in this location would directly impact the
release of these two specific hormones.
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Question 3
Hypersecretion of which hormone can lead to the condition known as Cushing's syndrome,
characterized by truncal obesity, a "moon face," and a "buffalo hump"?
A) Aldosterone
B) Thyroxine
C) Parathyroid Hormone (PTH)
D) Cortisol
E) Epinephrine
Correct Answer: D) Cortisol
Rationale: Cushing's syndrome is a disorder caused by prolonged exposure to high levels of
the glucocorticoid hormone cortisol, which is produced by the adrenal cortex. Excess
cortisol promotes the redistribution of body fat to the central regions, such as the face
(moon face), abdomen (truncal obesity), and the upper back (buffalo hump).
Question 4
Which of the following hormones operates via a positive feedback loop?
A) Thyroid Hormone
B) Insulin
C) Cortisol
D) Oxytocin
E) Parathyroid Hormone
Correct Answer: D) Oxytocin
Rationale: Most hormonal regulation occurs via negative feedback. Oxytocin is a primary
example of a hormone that uses a positive feedback mechanism. During childbirth, the
stretching of the cervix triggers the release of oxytocin, which in turn causes stronger
uterine contractions. These stronger contractions further stretch the cervix, leading to the
release of even more oxytocin, creating an amplifying cycle that continues until the baby is
born.
Question 5
What is the primary function of Aldosterone, a mineralocorticoid secreted by the adrenal cortex?
A) To increase the rate of metabolism.
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B) To increase blood calcium levels.
C) To increase the renal reabsorption of sodium and water.
D) To decrease blood glucose levels.
E) To stimulate the fight-or-flight response.
Correct Answer: C) To increase the renal reabsorption of sodium and water.
Rationale: Aldosterone is the principal mineralocorticoid. It acts on the distal convoluted
tubules and collecting ducts of the kidneys to increase the reabsorption of sodium (Na+)
from the filtrate back into the blood. Water follows the reabsorbed sodium osmotically,
which leads to an increase in blood volume and blood pressure.
Question 6
Blood returning to the heart from the pulmonary circuit first enters which chamber?
A) Right atrium
B) Right ventricle
C) Left atrium
D) Left ventricle
E) Pulmonary trunk
Correct Answer: C) Left atrium
Rationale: The pulmonary circuit involves the circulation of blood between the heart and
the lungs. After blood is oxygenated in the lungs, it is carried back to the heart via the four
pulmonary veins. These veins drain directly into the left atrium, which is the receiving
chamber for oxygenated blood.
Question 7
What event is represented by the QRS complex on an electrocardiogram (ECG)?
A) Atrial depolarization
B) Ventricular depolarization
C) Ventricular repolarization
D) Atrial repolarization
E) The delay at the AV node
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Correct Answer: B) Ventricular depolarization
Rationale: The ECG records the electrical activity of the heart. The QRS complex is the
largest wave and represents the rapid depolarization of the right and left ventricles as the
electrical impulse spreads through the ventricular myocardium. This electrical event
triggers ventricular contraction (systole). Atrial repolarization also occurs during this time
but is obscured by the much larger QRS complex.
Question 8
During the cardiac cycle, the closing of the atrioventricular (AV) valves (tricuspid and mitral)
produces which heart sound?
A) The first heart sound (S1)
B) The second heart sound (S2)
C) The third heart sound (S3)
D) The fourth heart sound (S4)
E) A heart murmur
Correct Answer: A) The first heart sound (S1)
Rationale: The first heart sound, often described as "lub," is produced by the closure of the
AV valves at the beginning of ventricular systole. This closure occurs when the pressure
inside the ventricles rises above the pressure in the atria, preventing the backflow of blood.
Question 9
According to the Frank-Starling law of the heart, an increase in end-diastolic volume (EDV) will
result in which of the following?
A) A decrease in the heart rate.
B) A decrease in stroke volume.
C) An increase in the force of ventricular contraction.
D) A decrease in cardiac output.
E) An increase in the duration of the QRS complex.
Correct Answer: C) An increase in the force of ventricular contraction.
Rationale: The Frank-Starling law states that the stroke volume of the heart increases in
response to an increase in the volume of blood filling the ventricles (the end-diastolic
Physiology III Complete Guide | 100% Correct| Grade A -Chamberlain
Question 1
Which hormone is released by the beta cells of the pancreas in response to high blood glucose
levels?
A) Glucagon
B) Somatostatin
C) Insulin
D) Cortisol
E) Gastrin
Correct Answer: C) Insulin
Rationale: The beta cells of the pancreatic islets are responsible for synthesizing and
secreting insulin. Insulin is an anabolic hormone that is released when blood glucose levels
are elevated, such as after a meal. It promotes the uptake, utilization, and storage of
glucose by body cells, particularly liver, muscle, and adipose tissue, thereby lowering blood
glucose levels.
Question 2
A client is diagnosed with a tumor in the posterior pituitary gland. The nurse would anticipate
that the secretion of which two hormones would be affected?
A) Growth Hormone (GH) and Prolactin (PRL)
B) Thyroid-Stimulating Hormone (TSH) and Adrenocorticotropic Hormone (ACTH)
C) Antidiuretic Hormone (ADH) and Oxytocin (OT)
D) Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH)
E) Melatonin and Calcitonin
Correct Answer: C) Antidiuretic Hormone (ADH) and Oxytocin (OT)
Rationale: The posterior pituitary does not produce hormones but rather stores and releases
two hormones that are produced in the hypothalamus: antidiuretic hormone (ADH) and
oxytocin. ADH is crucial for water reabsorption in the kidneys, and oxytocin is involved in
uterine contractions and milk ejection. A tumor in this location would directly impact the
release of these two specific hormones.
,[Type here]
Question 3
Hypersecretion of which hormone can lead to the condition known as Cushing's syndrome,
characterized by truncal obesity, a "moon face," and a "buffalo hump"?
A) Aldosterone
B) Thyroxine
C) Parathyroid Hormone (PTH)
D) Cortisol
E) Epinephrine
Correct Answer: D) Cortisol
Rationale: Cushing's syndrome is a disorder caused by prolonged exposure to high levels of
the glucocorticoid hormone cortisol, which is produced by the adrenal cortex. Excess
cortisol promotes the redistribution of body fat to the central regions, such as the face
(moon face), abdomen (truncal obesity), and the upper back (buffalo hump).
Question 4
Which of the following hormones operates via a positive feedback loop?
A) Thyroid Hormone
B) Insulin
C) Cortisol
D) Oxytocin
E) Parathyroid Hormone
Correct Answer: D) Oxytocin
Rationale: Most hormonal regulation occurs via negative feedback. Oxytocin is a primary
example of a hormone that uses a positive feedback mechanism. During childbirth, the
stretching of the cervix triggers the release of oxytocin, which in turn causes stronger
uterine contractions. These stronger contractions further stretch the cervix, leading to the
release of even more oxytocin, creating an amplifying cycle that continues until the baby is
born.
Question 5
What is the primary function of Aldosterone, a mineralocorticoid secreted by the adrenal cortex?
A) To increase the rate of metabolism.
,[Type here]
B) To increase blood calcium levels.
C) To increase the renal reabsorption of sodium and water.
D) To decrease blood glucose levels.
E) To stimulate the fight-or-flight response.
Correct Answer: C) To increase the renal reabsorption of sodium and water.
Rationale: Aldosterone is the principal mineralocorticoid. It acts on the distal convoluted
tubules and collecting ducts of the kidneys to increase the reabsorption of sodium (Na+)
from the filtrate back into the blood. Water follows the reabsorbed sodium osmotically,
which leads to an increase in blood volume and blood pressure.
Question 6
Blood returning to the heart from the pulmonary circuit first enters which chamber?
A) Right atrium
B) Right ventricle
C) Left atrium
D) Left ventricle
E) Pulmonary trunk
Correct Answer: C) Left atrium
Rationale: The pulmonary circuit involves the circulation of blood between the heart and
the lungs. After blood is oxygenated in the lungs, it is carried back to the heart via the four
pulmonary veins. These veins drain directly into the left atrium, which is the receiving
chamber for oxygenated blood.
Question 7
What event is represented by the QRS complex on an electrocardiogram (ECG)?
A) Atrial depolarization
B) Ventricular depolarization
C) Ventricular repolarization
D) Atrial repolarization
E) The delay at the AV node
, [Type here]
Correct Answer: B) Ventricular depolarization
Rationale: The ECG records the electrical activity of the heart. The QRS complex is the
largest wave and represents the rapid depolarization of the right and left ventricles as the
electrical impulse spreads through the ventricular myocardium. This electrical event
triggers ventricular contraction (systole). Atrial repolarization also occurs during this time
but is obscured by the much larger QRS complex.
Question 8
During the cardiac cycle, the closing of the atrioventricular (AV) valves (tricuspid and mitral)
produces which heart sound?
A) The first heart sound (S1)
B) The second heart sound (S2)
C) The third heart sound (S3)
D) The fourth heart sound (S4)
E) A heart murmur
Correct Answer: A) The first heart sound (S1)
Rationale: The first heart sound, often described as "lub," is produced by the closure of the
AV valves at the beginning of ventricular systole. This closure occurs when the pressure
inside the ventricles rises above the pressure in the atria, preventing the backflow of blood.
Question 9
According to the Frank-Starling law of the heart, an increase in end-diastolic volume (EDV) will
result in which of the following?
A) A decrease in the heart rate.
B) A decrease in stroke volume.
C) An increase in the force of ventricular contraction.
D) A decrease in cardiac output.
E) An increase in the duration of the QRS complex.
Correct Answer: C) An increase in the force of ventricular contraction.
Rationale: The Frank-Starling law states that the stroke volume of the heart increases in
response to an increase in the volume of blood filling the ventricles (the end-diastolic
