BIOS 255 / BIOS255 ANATOMY AND PHYSIOLOGY III ACTUAL EXAM
2026/2027 | COMPLETE EXAM-STYLE QUESTIONS | 100% VERIFIED –
DETAILED RATIONALES – PASS GUARANTEED – A+ GRADED
Here are 40 questions and answers with rationales for BIOS 255 (Anatomy & Physiology III with Lab),
focusing primarily on the **Cardiovascular, Respiratory, Renal, and Lymphatic/Immune systems** as
covered in typical final exams for this course .
---
### Questions 1-20: The Cardiovascular System (Heart & Hemodynamics)
**1. Which layer of the heart is directly responsible for the contractile force of the heart?**
A) Epicardium
B) Endocardium
C) Myocardium
D) Pericardium
**Answer: C**
**Rationale:** The *myocardium* is the middle, muscular layer responsible for contraction. The
epicardium is the visceral pericardium (outer layer), the endocardium lines the chambers, and the
pericardium is the protective sac .
**2. The right atrium receives blood from all EXCEPT:**
A) Superior vena cava
B) Inferior vena cava
C) Coronary sinus
D) Pulmonary veins
**Answer: D**
**Rationale:** The *pulmonary veins* return oxygenated blood to the *left* atrium. The right
atrium receives deoxygenated blood from the SVC, IVC, and coronary sinus .
, **3. The P wave on an ECG represents:**
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) AV nodal delay
**Answer: B**
**Rationale:** The P wave corresponds to *atrial depolarization* (contraction). The QRS complex
represents ventricular depolarization, and the T wave represents ventricular repolarization .
**4. Which heart valve has two cusps?**
A) Aortic
B) Pulmonary
C) Tricuspid
D) Mitral
**Answer: D**
**Rationale:** The *mitral* (bicuspid) valve has two cusps. The tricuspid has three, and the
semilunar valves (aortic/pulmonary) have three cusps each .
**5. The ductus arteriosus in fetal circulation connects:**
A) Right atrium to left atrium
B) Pulmonary trunk to aorta
C) Umbilical vein to inferior vena cava
D) Aorta to subclavian artery
**Answer: B**
**Rationale:** The *ductus arteriosus* shunts blood from the pulmonary trunk to the aorta,
bypassing the non-functioning fetal lungs .
**6. Which of the following vessels has the highest total cross-sectional area?**
A) Aorta
B) Arterioles
2026/2027 | COMPLETE EXAM-STYLE QUESTIONS | 100% VERIFIED –
DETAILED RATIONALES – PASS GUARANTEED – A+ GRADED
Here are 40 questions and answers with rationales for BIOS 255 (Anatomy & Physiology III with Lab),
focusing primarily on the **Cardiovascular, Respiratory, Renal, and Lymphatic/Immune systems** as
covered in typical final exams for this course .
---
### Questions 1-20: The Cardiovascular System (Heart & Hemodynamics)
**1. Which layer of the heart is directly responsible for the contractile force of the heart?**
A) Epicardium
B) Endocardium
C) Myocardium
D) Pericardium
**Answer: C**
**Rationale:** The *myocardium* is the middle, muscular layer responsible for contraction. The
epicardium is the visceral pericardium (outer layer), the endocardium lines the chambers, and the
pericardium is the protective sac .
**2. The right atrium receives blood from all EXCEPT:**
A) Superior vena cava
B) Inferior vena cava
C) Coronary sinus
D) Pulmonary veins
**Answer: D**
**Rationale:** The *pulmonary veins* return oxygenated blood to the *left* atrium. The right
atrium receives deoxygenated blood from the SVC, IVC, and coronary sinus .
, **3. The P wave on an ECG represents:**
A) Ventricular depolarization
B) Atrial depolarization
C) Ventricular repolarization
D) AV nodal delay
**Answer: B**
**Rationale:** The P wave corresponds to *atrial depolarization* (contraction). The QRS complex
represents ventricular depolarization, and the T wave represents ventricular repolarization .
**4. Which heart valve has two cusps?**
A) Aortic
B) Pulmonary
C) Tricuspid
D) Mitral
**Answer: D**
**Rationale:** The *mitral* (bicuspid) valve has two cusps. The tricuspid has three, and the
semilunar valves (aortic/pulmonary) have three cusps each .
**5. The ductus arteriosus in fetal circulation connects:**
A) Right atrium to left atrium
B) Pulmonary trunk to aorta
C) Umbilical vein to inferior vena cava
D) Aorta to subclavian artery
**Answer: B**
**Rationale:** The *ductus arteriosus* shunts blood from the pulmonary trunk to the aorta,
bypassing the non-functioning fetal lungs .
**6. Which of the following vessels has the highest total cross-sectional area?**
A) Aorta
B) Arterioles
