WGU D313 Anatomy and Physiology Objective
Assessment 2025
Accurate Exam Questions with Detailed Answers, Study Guide, and
Summarized Notes | Expert Verified for Guaranteed Pass | Latest Update
Multiple-Choice Questions
1. Which structure contains lubricating fluid that helps the heart to expand
and contract?
A. Pericardium
B. Pericardial cavity
C. Myocardium
D. Endocardium
Correct Answer: B. Pericardial cavity
Explanation: The pericardial cavity is the space between the parietal and visceral layers
of the pericardium, containing serous fluid that reduces friction during heart movements.
The pericardium is the protective sac around the heart, the myocardium is the cardiac
muscle, and the endocardium lines the heart’s interior.
2. Which chamber of the heart receives oxygenated blood from the lungs?
A. Right atrium
B. Right ventricle
C. Left atrium
D. Left ventricle
Correct Answer: C. Left atrium
Explanation: The left atrium receives oxygenated blood from the lungs via the pul-
monary veins. The right atrium receives deoxygenated blood, while the ventricles pump
blood out of the heart.
3. What is the cardiac muscle of the heart called?
A. Epicardium
B. Myocardium
C. Endocardium
D. Pericardium
Correct Answer: B. Myocardium
Explanation: The myocardium is the thick, muscular layer of the heart responsible for
its contractile function. The epicardium is the outer layer, the endocardium lines the
chambers, and the pericardium is the external sac.
1
,4. Which artery becomes the femoral artery once it leaves the body cavity?
A. Internal iliac artery
B. External iliac artery
C. Common iliac artery
D. Aorta
Correct Answer: B. External iliac artery
Explanation: The external iliac artery continues as the femoral artery after passing
through the inguinal ligament into the thigh. The internal iliac supplies the pelvis, the
common iliac splits into internal and external, and the aorta is the main artery.
5. Which heart sound corresponds to the closing of the bicuspid valve?
A. S1
B. S2
C. S3
D. S4
Correct Answer: A. S1
Explanation: The S1 sound, or “lub,” occurs when the atrioventricular valves (bicus-
pid/mitral and tricuspid) close at the start of systole. S2 is associated with semilunar
valve closure, while S3 and S4 are abnormal sounds in some cases.
6. What is the role of pulmonary surfactant in the respiratory system?
A. Increases surface tension in alveoli
B. Decreases surface tension in alveoli
C. Traps pathogens in the airways
D. Facilitates mucus production
Correct Answer: B. Decreases surface tension in alveoli
Explanation: Pulmonary surfactant, produced by type II alveolar cells, reduces surface
tension in the alveoli, preventing their collapse during exhalation and aiding efficient gas
exchange.
7. Which cells secrete mucus into the respiratory airways?
A. Goblet cells
B. Ciliated cells
C. Alveolar macrophages
D. Type I alveolar cells
Correct Answer: A. Goblet cells
Explanation: Goblet cells in the respiratory epithelium secrete mucus to trap particles
2
, and pathogens. Ciliated cells move mucus, alveolar macrophages engulf debris, and type
I alveolar cells form the gas exchange surface.
8. Why do we need to breathe?
A. To store air for speech
B. To gain O2 and eliminate CO2
C. To regulate body temperature
D. To produce energy directly
Correct Answer: B. To gain O2 and eliminate CO2
Explanation: Breathing facilitates gas exchange, delivering oxygen for cellular respira-
tion and removing carbon dioxide, a waste product, to maintain blood pH and support
metabolism.
9. What is the main function of thyroid-stimulating hormone (TSH)?
A. Stimulates adrenal hormone release
B. Stimulates thyroid hormone release
C. Regulates blood calcium levels
D. Promotes glucose uptake
Correct Answer: B. Stimulates thyroid hormone release
Explanation: TSH, secreted by the anterior pituitary, stimulates the thyroid gland to
produce and release thyroid hormones (T3 and T4), which regulate metabolism.
10. In males, where is testosterone primarily produced?
A. Adrenal glands
B. Testes
C. Pituitary gland
D. Hypothalamus
Correct Answer: B. Testes
Explanation: Testosterone is primarily produced by Leydig cells in the testes. The
adrenal glands produce small amounts, while the pituitary and hypothalamus regulate
its production.
11. How do steroid hormones generally exert their effects?
A. Activate second messenger systems
B. Bind to cell surface receptors
C. Bind to DNA receptors to alter transcription
D. Inhibit neurotransmitter release
3
Assessment 2025
Accurate Exam Questions with Detailed Answers, Study Guide, and
Summarized Notes | Expert Verified for Guaranteed Pass | Latest Update
Multiple-Choice Questions
1. Which structure contains lubricating fluid that helps the heart to expand
and contract?
A. Pericardium
B. Pericardial cavity
C. Myocardium
D. Endocardium
Correct Answer: B. Pericardial cavity
Explanation: The pericardial cavity is the space between the parietal and visceral layers
of the pericardium, containing serous fluid that reduces friction during heart movements.
The pericardium is the protective sac around the heart, the myocardium is the cardiac
muscle, and the endocardium lines the heart’s interior.
2. Which chamber of the heart receives oxygenated blood from the lungs?
A. Right atrium
B. Right ventricle
C. Left atrium
D. Left ventricle
Correct Answer: C. Left atrium
Explanation: The left atrium receives oxygenated blood from the lungs via the pul-
monary veins. The right atrium receives deoxygenated blood, while the ventricles pump
blood out of the heart.
3. What is the cardiac muscle of the heart called?
A. Epicardium
B. Myocardium
C. Endocardium
D. Pericardium
Correct Answer: B. Myocardium
Explanation: The myocardium is the thick, muscular layer of the heart responsible for
its contractile function. The epicardium is the outer layer, the endocardium lines the
chambers, and the pericardium is the external sac.
1
,4. Which artery becomes the femoral artery once it leaves the body cavity?
A. Internal iliac artery
B. External iliac artery
C. Common iliac artery
D. Aorta
Correct Answer: B. External iliac artery
Explanation: The external iliac artery continues as the femoral artery after passing
through the inguinal ligament into the thigh. The internal iliac supplies the pelvis, the
common iliac splits into internal and external, and the aorta is the main artery.
5. Which heart sound corresponds to the closing of the bicuspid valve?
A. S1
B. S2
C. S3
D. S4
Correct Answer: A. S1
Explanation: The S1 sound, or “lub,” occurs when the atrioventricular valves (bicus-
pid/mitral and tricuspid) close at the start of systole. S2 is associated with semilunar
valve closure, while S3 and S4 are abnormal sounds in some cases.
6. What is the role of pulmonary surfactant in the respiratory system?
A. Increases surface tension in alveoli
B. Decreases surface tension in alveoli
C. Traps pathogens in the airways
D. Facilitates mucus production
Correct Answer: B. Decreases surface tension in alveoli
Explanation: Pulmonary surfactant, produced by type II alveolar cells, reduces surface
tension in the alveoli, preventing their collapse during exhalation and aiding efficient gas
exchange.
7. Which cells secrete mucus into the respiratory airways?
A. Goblet cells
B. Ciliated cells
C. Alveolar macrophages
D. Type I alveolar cells
Correct Answer: A. Goblet cells
Explanation: Goblet cells in the respiratory epithelium secrete mucus to trap particles
2
, and pathogens. Ciliated cells move mucus, alveolar macrophages engulf debris, and type
I alveolar cells form the gas exchange surface.
8. Why do we need to breathe?
A. To store air for speech
B. To gain O2 and eliminate CO2
C. To regulate body temperature
D. To produce energy directly
Correct Answer: B. To gain O2 and eliminate CO2
Explanation: Breathing facilitates gas exchange, delivering oxygen for cellular respira-
tion and removing carbon dioxide, a waste product, to maintain blood pH and support
metabolism.
9. What is the main function of thyroid-stimulating hormone (TSH)?
A. Stimulates adrenal hormone release
B. Stimulates thyroid hormone release
C. Regulates blood calcium levels
D. Promotes glucose uptake
Correct Answer: B. Stimulates thyroid hormone release
Explanation: TSH, secreted by the anterior pituitary, stimulates the thyroid gland to
produce and release thyroid hormones (T3 and T4), which regulate metabolism.
10. In males, where is testosterone primarily produced?
A. Adrenal glands
B. Testes
C. Pituitary gland
D. Hypothalamus
Correct Answer: B. Testes
Explanation: Testosterone is primarily produced by Leydig cells in the testes. The
adrenal glands produce small amounts, while the pituitary and hypothalamus regulate
its production.
11. How do steroid hormones generally exert their effects?
A. Activate second messenger systems
B. Bind to cell surface receptors
C. Bind to DNA receptors to alter transcription
D. Inhibit neurotransmitter release
3
