The smooth, thin membrane that lines the chambers of the heart and forms the surface of the heart valves is the:
Pericardium.
Endocardium.
Myocardium.
Epicardium.
The Correct Answer is B
The endocardium is the thin inner lining of the heart chambers and also forms the surface of the heart valves.
Some possible explanations for the other choices are:
Choice A is wrong because the pericardium is the sac that surrounds the heart and consists of two layers: the fibrous pericardium and the serous pericardium.
Choice C is wrong because the myocardium is the thick middle layer of muscle that allows the heart chambers to contract and relax to pump blood to the body.
Choice D is wrong because epicardium is another name for the visceral layer of the serous pericardium that is fused to the heart and is part of the heart wall.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Capillary walls consist of a single layer of epithelial cells, and they exchange substances in the blood for substances in the tissue fluid surrounding body cells.
This single layer of cells is called the endothelium and it forms the barrier between the blood and the interstitial fluid.
The endothelium can be either continuous or fenestrated, depending on the tissue type and function.
The capillaries are very thin and allow red blood cells to flow through them single file.
The capillaries also have a layer of a glycoprotein called the glycocalyx that covers their luminal surface.
Choice B. False is wrong because it contradicts the definition and structure of capillaries.
Capillaries are not made of multiple layers of cells, nor do they prevent the exchange of substances between the blood and the tissue fluid.
Correct Answer is A
Explanation
The mitral valve lies between the left atrium and left ventricle and prevents the regurgitation of blood from the ventricle back into the atrium.
It has two leaflets that open and close to allow blood to flow from the lungs into the left atrium and then to the left ventricle.
Choice B is wrong because the tricuspid valve lies between the right atrium and right ventricle and prevents the regurgitation of blood from the ventricle back into the atrium.
It has three leaflets that open and close to allow blood to flow from the body into the right atrium and then to the right ventricle.
Choice C is wrong because the pulmonary valve lies between the right ventricle and the pulmonary artery and prevents the regurgitation of blood from the artery back into the ventricle.
It has three leaflets that open and close to allow blood to flow from the right ventricle to the lungs, where it picks up oxygen.
Choice D is wrong because the aortic valve lies between the left ventricle and the aorta and prevents the regurgitation of blood from the aorta back into the ventricle.
It has three leaflets that open and close to allow blood to flow from the left ventricle to the rest of the body.
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