What is the primary difference between veins and arteries?
Arteries have thicker walls than veins.
Veins have no valves, while arteries have valves.
Arteries have larger lumens compared to veins.
Arteries carry blood to the heart, while veins carry blood away from the heart.
The Correct Answer is A
A. Arteries have thicker walls than veins:
Arteries have thicker walls composed of more smooth muscle and elastic tissue to withstand the high pressure of blood ejected from the heart. Veins have thinner walls and larger lumens because they operate under lower pressure and rely on valves and skeletal muscle pumps to return blood to the heart.
B. Veins have no valves, while arteries have valves:
This is incorrect because veins have valves to prevent backflow of blood, especially in the extremities. Arteries do not need valves because blood is propelled by high pressure from ventricular contraction.
C. Arteries have larger lumens compared to veins:
Veins generally have larger lumens than arteries, allowing them to act as capacitance vessels that store blood. Arteries have smaller lumens relative to their wall thickness.
D. Arteries carry blood to the heart, while veins carry blood away from the heart:
This reverses the roles. Arteries carry blood away from the heart, while veins carry blood back to the heart. Proper understanding of directionality is crucial in circulatory physiology.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
A. To increase blood volume and systemic vascular resistance:
The RAAS system increases blood pressure by two main mechanisms: angiotensin II causes vasoconstriction, raising systemic vascular resistance, and aldosterone promotes sodium and water retention, increasing blood volume. Together, these actions restore perfusion pressure in hypotensive states.
B. To decrease heart rate and reduce cardiac output:
RAAS does not directly affect heart rate; it works primarily on vascular tone and fluid retention, not cardiac chronotropy.
C. To regulate oxygen levels in the blood:
Oxygen sensing is mainly controlled by chemoreceptors, not RAAS.
D. To control nerve impulses to the heart:
RAAS does not directly regulate cardiac conduction or nerve impulses; it acts on vascular smooth muscle and renal sodium retention.
Correct Answer is A
Explanation
A. Left anterior descending artery:
The LAD artery is the main supplier of the anterior wall of the left ventricle and the interventricular septum, which is crucial for coordinated ventricular contraction. Occlusion can cause a large anterior myocardial infarction and severe left ventricular dysfunction.
B. Right coronary artery:
The RCA primarily supplies the right atrium, right ventricle, and inferior wall of the left ventricle. It has a lesser role in anterior left ventricular perfusion.
C. Posterior descending artery:
The PDA supplies the inferior septum and posterior left ventricle, not the anterior wall or majority of the left ventricle.
D. Circumflex artery:
The circumflex artery supplies the lateral and posterior walls of the left ventricle. It does not supply the anterior wall or the main interventricular septum.
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