Which of the following heart valves lies between the left atrium and left ventricle and prevents the regurgitation of blood from the ventricle back into the atrium?
Mitral valve.
Tricuspid valve.
Pulmonary valve.
Aortic valve.
The Correct Answer is A
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.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
The thymus gland is an essential part of the immune system that produces and matures T cells, a type of white blood cell that defends the body from infections.
Thymosins also regulate immune cell production and inhibit aging.
Choice A is wrong because thyroxines are hormones produced by the thyroid gland, not the thymus gland.
Thyroxines control metabolism and affect growth and development.
Choice B is wrong because melatonins are hormones produced by the pineal gland, not the thymus gland.
Melatonins control circadian rhythms and sleep cycles.
Choice D is wrong because prostaglandins are not hormones, but lipid compounds that have hormone-like effects.
Prostaglandins control inflammation, blood pressure, muscle contraction, and other functions.
Correct Answer is C
Explanation
It explains that the primary immune response produces antibodies within five to ten days of exposure to antigens, while the secondary immune response produces antibodies within a day or two of subsequent exposure to the same antigen.
This is because the primary immune response involves the activation and differentiation of naive B cells into plasma cells and memory cells, while the secondary immune response involves the rapid activation of memory cells into plasma cells.
Choice A is wrong because the primary and secondary immune responses can occur in both children and adults.
Choice B is wrong because the primary immune response is slower than the secondary immune response in producing antibodies.
Choice D is wrong because both primary and secondary immune responses are important for the body’s ability to protect itself from pathogens.
The primary immune response generates immunological memory, while the secondary immune response provides a faster and stronger response to repeated infections.
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