BIOS 255 / BIOS255 Exam 1: Anatomy & Physiology III
with Lab Latest update 2026/2027 | Chamberlain |
Q&A with Rationales | Grade A | Pass Guaranteed
A+ Graded
Q1. A patient presents with a heart rate of 75 beats/min and a stroke volume of 70 mL/beat.
What is their cardiac output?
A. 4.5 L/min
B. 5.25 L/min
C. 6.0 L/min
D. 5250 mL/min
Correct Answer: B
Rationale: Correct because cardiac output (CO) is calculated by multiplying heart rate
(HR) by stroke volume (SV). CO = 75 beats/min × 70 mL/beat = 5250 mL/min, which
converts to 5.25 L/min. This matches the standard hemodynamic formula taught in
BIOS255.
Q2. [SATA] Which of the following formed elements are derived from the myeloid stem cell
line?
A. T-lymphocytes
B. Erythrocytes
C. Platelets
D. B-lymphocytes
E. Neutrophils
Correct Answer: B, C, E
Rationale: Correct because erythrocytes (RBCs), platelets (via megakaryocytes), and
neutrophils all originate from the common myeloid progenitor. Lymphocytes (T and B
cells) arise from the lymphoid stem cell line, making A and D incorrect.
, Q3. During the cardiac cycle, the first heart sound (S1) is caused by the closure of which valves?
A. Aortic and pulmonary valves
B. Mitral and tricuspid valves
C. Semilunar valves
D. All four valves simultaneously
Correct Answer: B
Rationale: Correct because S1 ("lub") marks the beginning of ventricular systole and is
produced by the closure of the atrioventricular (AV) valves—specifically the mitral
(bicuspid) and tricuspid valves. This prevents backflow into the atria.
Q4. A patient with a deep laceration is experiencing uncontrolled bleeding. Which step of
hemostasis occurs immediately after vascular spasm?
A. Fibrinolysis
B. Platelet plug formation
C. Coagulation cascade
D. Clot retraction
Correct Answer: B
Rationale: Correct because the sequence of hemostasis is: 1) Vascular spasm, 2) Platelet
plug formation (primary hemostasis), and 3) Coagulation (secondary hemostasis). Platelets
adhere to exposed collagen immediately after the vessel constricts.
Q5. Which lead placement is used to view the electrical activity of the heart in the frontal plane?
A. V1-V6
B. Limb leads (I, II, III, aVR, aVL, aVF)
C. Precordial leads only
D. Esophageal lead
Correct Answer: B
Rationale: Correct because the limb leads (bipolar I, II, III and augmented aVR, aVL,
aVF) record electrical potential differences in the frontal plane. Precordial leads (V1-V6)
view the horizontal plane.
with Lab Latest update 2026/2027 | Chamberlain |
Q&A with Rationales | Grade A | Pass Guaranteed
A+ Graded
Q1. A patient presents with a heart rate of 75 beats/min and a stroke volume of 70 mL/beat.
What is their cardiac output?
A. 4.5 L/min
B. 5.25 L/min
C. 6.0 L/min
D. 5250 mL/min
Correct Answer: B
Rationale: Correct because cardiac output (CO) is calculated by multiplying heart rate
(HR) by stroke volume (SV). CO = 75 beats/min × 70 mL/beat = 5250 mL/min, which
converts to 5.25 L/min. This matches the standard hemodynamic formula taught in
BIOS255.
Q2. [SATA] Which of the following formed elements are derived from the myeloid stem cell
line?
A. T-lymphocytes
B. Erythrocytes
C. Platelets
D. B-lymphocytes
E. Neutrophils
Correct Answer: B, C, E
Rationale: Correct because erythrocytes (RBCs), platelets (via megakaryocytes), and
neutrophils all originate from the common myeloid progenitor. Lymphocytes (T and B
cells) arise from the lymphoid stem cell line, making A and D incorrect.
, Q3. During the cardiac cycle, the first heart sound (S1) is caused by the closure of which valves?
A. Aortic and pulmonary valves
B. Mitral and tricuspid valves
C. Semilunar valves
D. All four valves simultaneously
Correct Answer: B
Rationale: Correct because S1 ("lub") marks the beginning of ventricular systole and is
produced by the closure of the atrioventricular (AV) valves—specifically the mitral
(bicuspid) and tricuspid valves. This prevents backflow into the atria.
Q4. A patient with a deep laceration is experiencing uncontrolled bleeding. Which step of
hemostasis occurs immediately after vascular spasm?
A. Fibrinolysis
B. Platelet plug formation
C. Coagulation cascade
D. Clot retraction
Correct Answer: B
Rationale: Correct because the sequence of hemostasis is: 1) Vascular spasm, 2) Platelet
plug formation (primary hemostasis), and 3) Coagulation (secondary hemostasis). Platelets
adhere to exposed collagen immediately after the vessel constricts.
Q5. Which lead placement is used to view the electrical activity of the heart in the frontal plane?
A. V1-V6
B. Limb leads (I, II, III, aVR, aVL, aVF)
C. Precordial leads only
D. Esophageal lead
Correct Answer: B
Rationale: Correct because the limb leads (bipolar I, II, III and augmented aVR, aVL,
aVF) record electrical potential differences in the frontal plane. Precordial leads (V1-V6)
view the horizontal plane.
