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Heart Anatomy & Cardiac Physiology
Q1: While viewing a dissected heart in the anatomy lab, you identify the layer of the
heart wall that is composed of cardiac muscle tissue and is responsible for the pumping
action of the heart. Which specific layer is this?
A. Epicardium
B. Myocardium
C. Endocardium
D. Pericardium
Correct Answer: B
Rationale: The best answer is B because the myocardium is the thick, muscular middle
layer of the heart wall that contracts to pump blood, whereas the epicardium is the outer
layer and the endocardium is the inner lining.
Q2: During the cardiac cycle, the atrioventricular (AV) valves must close to prevent
backflow of blood into the atria. Which structure attached to the AV valves helps prevent
them from everting (prolapsing) into the atria during ventricular contraction?
A. Chordae tendineae
B. Papillary muscles
C. Pectinate muscles
D. Trabeculae carneae
Correct Answer: A
Rationale: This choice is correct because the chordae tendineae are strong fibrous
strings that connect the AV valve cusps to the papillary muscles, anchoring the valves
so they don't flip inside out under high pressure.
Q3: A patient is diagnosed with aortic valve stenosis. This valve is located between
which two structures?
A. Right atrium and right ventricle
B. Left atrium and left ventricle
C. Right ventricle and pulmonary trunk
D. Left ventricle and aorta
, Correct Answer: D
Rationale: This matches the anatomy covered in Module 3 where the aortic semilunar
valve guards the exit between the left ventricle and the ascending aorta to prevent blood
from flowing back into the heart.
Q4: The electrical conduction system of the heart initiates the heartbeat at the
pacemaker. Which structure is known as the natural pacemaker of the heart due to its
intrinsic firing rate of 60-100 times per minute?
A. Atrioventricular (AV) node
B. Bundle of His
C. Sinoatrial (SA) node
D. Purkinje fibers
Correct Answer: C
Rationale: The best answer is C because the SA node, located in the right atrium, has
the fastest inherent rate of depolarization and sets the rhythm for the entire heart.
Q5: On an ECG tracing, the electrical event that corresponds to ventricular
depolarization (and subsequently ventricular contraction) is represented by which wave
or complex?
A. P wave
B. QRS complex
C. T wave
D. PR interval
Correct Answer: B
Rationale: This choice is correct because the QRS complex represents the rapid
depolarization of the ventricles, which triggers the contraction necessary to pump blood
out to the lungs and body.
Q6: Cardiac muscle cells are connected by specialized intercellular junctions that allow
ions to pass freely from cell to cell, ensuring the heart contracts as a single,
synchronized unit. These junctions are called:
A. Tight junctions
B. Gap junctions
C. Desmosomes
D. Fascia adherens
Correct Answer: B
Rationale: This aligns with the histology principles we studied where gap junctions
found within intercalated discs allow for rapid electrical coupling (action potential
spread) between cardiac myocytes.
Q7: Which vessel carries deoxygenated blood from the right ventricle to the lungs?