Which cardiac chamber has the thinnest wall and why?
The right and left atria because they are low pressure chambers that serve as storage units and conduits for blood.
The right and left atria because they are not involved directly in the preloaded, contractility or afterload of the heart
The left ventricle because the mean pressure of blood coming into the ventricle is from the lung, which has a low pressure
The right ventricle because it pumps blood into the pulmonary capillaries, which have a lower pressure compared with the systemic circulation
The Correct Answer is A
The walls of the atria are thin because they do not generate as much pressure as the ventricles, as their main function is to receive blood from the veins and pump it into the ventricles. The ventricles have thicker walls because they are responsible for generating the force necessary to pump blood out of the heart and into the systemic or pulmonary circulation.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
associated with chronic heart failure. Activation of the RAAS system occurs as a compensatory mechanism in response to decreased cardiac output and reduced renal perfusion. The renin-angiotensin-aldosterone system increases blood pressure, maintains blood volume and improves cardiac contractility in the short term, but in the long term it can lead to fluid retention, edema, and worsen cardiac function.
Correct Answer is B
Explanation
The mitral and tricuspid valves are located between the atria and ventricles in the heart, and they open and close to allow blood to flow in one direction through the heart. During diastole, when the heart is relaxed and filling with blood, the mitral and tricuspid valves are open to allow blood to flow from the atria into the ventricles.
Once the ventricles are filled with blood, they begin to contract during systole to pump the blood out to the lungs (right ventricle) and the rest of the body (left ventricle). As the ventricles contract, the pressure within them increases, which causes the mitral and tricuspid valves to be pushed closed by the blood within the ventricles. This closure prevents the backflow of blood into the atria during ventricular contraction (systole).
The chordae tendineae are thin, fibrous cords that connect the mitral and tricuspid valves to the papillary muscles within the ventricles. These structures help to anchor the valves in place during ventricular contraction, and prevent them from prolapsing (bulging back into the atria) and causing regurgitation (backflow of blood).
The trabeculae carneae are muscular ridges within the ventricles that help to increase the force of ventricular contraction, but they do not play a direct role in closing the mitral and tricuspid valves. Similarly, the reduced pressure in the atria during ventricular contraction is due to the fact that blood is being pumped out of the atria and into the ventricles, rather than the atria "pulling" the valves closed.
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