BIO 117 – Exam 3 Practice Questions Exam (Latest 2026) Questions with
Revised Answers, (A+ Guarantee) LATEST UPDATE
1. Which chamber of the heart receives oxygenated blood from the lungs?
a) Right atrium
b) Right ventricle
c) Left atrium
d) Left ventricle
Rationale: The left atrium receives oxygen-rich blood from the pulmonary veins.
2. Which valve prevents backflow from the left ventricle into the left atrium?
a) Tricuspid
b) Pulmonary
c) Mitral (bicuspid)
d) Aortic
Rationale: The mitral valve allows blood flow from the left atrium to ventricle and prevents
backflow.
3. The “lub” sound of the heartbeat is caused by:
a) Ventricular filling
b) Closure of AV valves
c) Closure of semilunar valves
d) Ventricular contraction
Rationale: “Lub” corresponds to AV valves (tricuspid and mitral) closing at systole start.
4. The primary pacemaker of the heart is:
a) AV node
b) Purkinje fibers
c) Bundle of His
d) SA node
Rationale: SA node initiates the electrical impulse, controlling heart rate.
, 5. Which blood vessel carries oxygenated blood to the body?
a) Pulmonary artery
b) Aorta
c) Pulmonary vein
d) Superior vena cava
Rationale: The aorta distributes oxygen-rich blood from the left ventricle to the systemic
circulation.
6. During ventricular systole, blood is ejected into the:
a) Aorta and pulmonary artery
b) Left atrium only
c) Right atrium only
d) Coronary sinus
Rationale: Ventricular contraction pumps blood into the systemic and pulmonary arteries.
7. Which structure connects atria and ventricles electrically?
a) SA node
b) Purkinje fibers
c) AV node
d) Bundle branches
Rationale: AV node delays the impulse to allow atrial contraction before ventricular contraction.
8. Which type of blood vessel has the thickest tunica media?
a) Vein
b) Capillary
c) Artery
d) Venule
Rationale: Arteries have thick muscular walls to withstand high pressure.
9. Which vessel is the site of nutrient and gas exchange?
a) Artery
b) Vein
c) Capillary
d) Arterioles
Rationale: Capillaries’ thin walls allow diffusion of gases, nutrients, and waste.
10. Blood pressure is highest in the:
a) Capillaries
b) Veins
c) Aorta
d) Venules
Rationale: Blood leaving the left ventricle enters the aorta under high pressure.
11. Which is the normal stimulus for breathing?
a) Oxygen level in lungs
Revised Answers, (A+ Guarantee) LATEST UPDATE
1. Which chamber of the heart receives oxygenated blood from the lungs?
a) Right atrium
b) Right ventricle
c) Left atrium
d) Left ventricle
Rationale: The left atrium receives oxygen-rich blood from the pulmonary veins.
2. Which valve prevents backflow from the left ventricle into the left atrium?
a) Tricuspid
b) Pulmonary
c) Mitral (bicuspid)
d) Aortic
Rationale: The mitral valve allows blood flow from the left atrium to ventricle and prevents
backflow.
3. The “lub” sound of the heartbeat is caused by:
a) Ventricular filling
b) Closure of AV valves
c) Closure of semilunar valves
d) Ventricular contraction
Rationale: “Lub” corresponds to AV valves (tricuspid and mitral) closing at systole start.
4. The primary pacemaker of the heart is:
a) AV node
b) Purkinje fibers
c) Bundle of His
d) SA node
Rationale: SA node initiates the electrical impulse, controlling heart rate.
, 5. Which blood vessel carries oxygenated blood to the body?
a) Pulmonary artery
b) Aorta
c) Pulmonary vein
d) Superior vena cava
Rationale: The aorta distributes oxygen-rich blood from the left ventricle to the systemic
circulation.
6. During ventricular systole, blood is ejected into the:
a) Aorta and pulmonary artery
b) Left atrium only
c) Right atrium only
d) Coronary sinus
Rationale: Ventricular contraction pumps blood into the systemic and pulmonary arteries.
7. Which structure connects atria and ventricles electrically?
a) SA node
b) Purkinje fibers
c) AV node
d) Bundle branches
Rationale: AV node delays the impulse to allow atrial contraction before ventricular contraction.
8. Which type of blood vessel has the thickest tunica media?
a) Vein
b) Capillary
c) Artery
d) Venule
Rationale: Arteries have thick muscular walls to withstand high pressure.
9. Which vessel is the site of nutrient and gas exchange?
a) Artery
b) Vein
c) Capillary
d) Arterioles
Rationale: Capillaries’ thin walls allow diffusion of gases, nutrients, and waste.
10. Blood pressure is highest in the:
a) Capillaries
b) Veins
c) Aorta
d) Venules
Rationale: Blood leaving the left ventricle enters the aorta under high pressure.
11. Which is the normal stimulus for breathing?
a) Oxygen level in lungs
