The mitral and tricuspid valves close after the ventricles are filled with blood because the
Chordae tendineae relax, which allows the valves to close.
Increased pressure in the ventricles pushes the valves to close.
Trabeculae carneae contract, which pulls the valves closed.
Reduced pressure in the atria creates a negative pressure that pulls the valves closed.
The Correct Answer is B
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.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Atherosclerosis is a disease in which fatty deposits (plaques) build up in the walls of arteries, leading to narrowing and reduced blood flow. Elevated levels of certain lipids, including low density lipoprotein (LDL) cholesterol and triglycerides, are well-established risk factors for the development of atherosclerosis.
In contrast, high density lipoprotein (HDL) cholesterol has been shown to have a protective effect against atherosclerosis. HDL is often referred to as "good cholesterol" because it helps to transport excess cholesterol from peripheral tissues (including the walls of arteries) back to the liver for processing and excretion. HDL also has anti-inflammatory and antioxidant properties that may help to reduce the risk of atherosclerosis.
In general, higher levels of HDL cholesterol are associated with a lower risk of cardiovascular disease and atherosclerosis. However, the protective effect of HDL may vary depending on other factors such as smoking, obesity, and diabetes. It is important to maintain a healthy balance of lipids in the bloodstream, including a high level of HDL and low levels of LDL and triglycerides, in order to reduce the risk of atherosclerosis and other cardiovascular diseases.
Correct Answer is C
Explanation
When the left ventricle is unable to pump blood effectively, blood backs up into the lungs, leading to pulmonary congestion and edema. This can cause symptoms such as shortness of breath, coughing, and wheezing. Decreased venous pressure and hyperoxygenation are not typically associated with left ventricular failure. Bradycardia may occur in some cases, but it is not a defining feature of left ventricular failure.
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