Questions with Answers & Explanations | A&P Study Guide
Section 1: Cardiovascular System (Questions 1–35)
1. Which layer of the heart is responsible for the contraction of the heart muscle?
A) Epicardium
B) Myocardium
C) Endocardium
D) Pericardium
Answer: B
Explanation: The myocardium is the middle, muscular layer responsible for heart contractions. The
epicardium is the outer layer; endocardium lines the chambers.
2. True or False: The left ventricle has a thicker wall than the right ventricle because it pumps blood to
the systemic circulation.
Answer: True
Explanation: The left ventricle generates higher pressure to overcome systemic resistance; the right
ventricle pumps to the low‑resistance pulmonary circuit.
3. Which valve prevents backflow of blood from the left ventricle into the left atrium?
A) Tricuspid valve
B) Pulmonary valve
C) Aortic valve
D) Mitral (bicuspid) valve
Answer: D
,Explanation: The mitral (bicuspid) valve is between the left atrium and left ventricle. The tricuspid is on
the right side.
4. True or False: The pulmonary artery carries oxygenated blood to the lungs.
Answer: False
Explanation: The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs for
oxygenation.
5. The cardiac conduction structure that initiates the heartbeat is the:
A) Atrioventricular (AV) node
B) Purkinje fibers
C) Sinoatrial (SA) node
D) Bundle of His
Answer: C
Explanation: The SA node is the natural pacemaker, generating electrical impulses that set the heart
rate.
6. True or False: The P wave on an ECG represents ventricular depolarization.
Answer: False
Explanation: The P wave represents atrial depolarization. The QRS complex represents ventricular
depolarization.
7. A patient has a blood pressure of 140/90 mmHg. Which of the following is the mean arterial pressure
(MAP) approximately?
A) 100 mmHg
B) 107 mmHg
C) 90 mmHg
D) 120 mmHg
,Answer: B
Explanation: MAP = DBP + 1/3(SBP – DBP) = 90 + 1/3(50) = 90 + 16.7 = 106.7 mmHg.
8. True or False: Baroreceptors located in the carotid sinus and aortic arch detect changes in blood
pressure.
Answer: True
Explanation: Baroreceptors monitor stretch; they signal the medulla to adjust heart rate and vessel
diameter.
9. Which of the following is a function of the lymphatic system?
A) Return interstitial fluid to the bloodstream
B) Transport dietary lipids
C) Immune surveillance
D) All of the above
Answer: D
Explanation: The lymphatic system maintains fluid balance, absorbs fats (lacteals), and houses
lymphocytes.
10. True or False: The largest lymphatic vessel is the thoracic duct, which drains lymph from most of the
body.
Answer: True
Explanation: The thoracic duct drains the left side of the head, left arm, and entire lower body; the right
lymphatic duct drains the right upper quadrant.
11. Which blood vessel type has the thickest tunica media and the highest elasticity?
A) Capillaries
B) Venules
C) Arteries (especially elastic arteries)
D) Veins
, Answer: C
Explanation: Elastic arteries (e.g., aorta) have many elastic fibers to dampen pressure oscillations.
12. True or False: Venous return is aided by skeletal muscle contractions and respiratory movements.
Answer: True
Explanation: The skeletal muscle pump and thoracic pump help propel blood back to the heart against
gravity.
13. Which of the following is a risk factor for hypertension?
A) High sodium intake
B) Obesity
C) Sedentary lifestyle
D) All of the above
Answer: D
Explanation: Modifiable risk factors include diet, weight, exercise, and stress.
14. True or False: The Frank‑Starling law states that stroke volume increases as end‑diastolic volume
increases.
Answer: True
Explanation: Increased preload stretches the myocardium, leading to a more forceful contraction.
15. Which hormone causes vasoconstriction and increases blood pressure?
A) Atrial natriuretic peptide (ANP)
B) Angiotensin II
C) Bradykinin
D) Nitric oxide