Nursing Elites

1. Which of the following cardiac valves prevents blood from returning to the left ventricle of the heart?

• A. pulmonic
• B. mitral
• C. tricuspid
• D. aortic

Correct answer: D

Rationale: The correct answer is the aortic valve. The aortic valve is located between the left ventricle and the aorta, preventing the backflow of blood into the left ventricle once it has been pumped out during systole. Choice A, pulmonic, is incorrect as it is associated with the right side of the heart. Choice B, mitral, is incorrect as it is the valve between the left atrium and ventricle. Choice C, tricuspid, is incorrect as it is located between the right atrium and ventricle.

2. Which of the following is a role of platelets in hemostasis?

• A. formation of plugs
• B. promotion of vasodilation
• C. conversion of prothrombin to thrombin
• D. activation of calcium

Correct answer: A

Rationale: Platelets play a crucial role in hemostasis by forming plugs to stop bleeding. Choice B is incorrect because platelets do not promote vasodilation; instead, they help in vasoconstriction. Choice C is incorrect as the conversion of prothrombin to thrombin is a function of the coagulation cascade involving various clotting factors, not platelets. Choice D is incorrect as platelets do not directly activate calcium; instead, they play a role in the activation of other clotting factors.

3. Metabolism is defined as _____.

• A. the removal of wastes produced by chemical reactions
• B. the breakdown of substances into simpler forms
• C. the taking in of nutrients
• D. all the chemical reactions occurring in an organism that support life

Correct answer: D

Rationale: Metabolism refers to all the chemical reactions that take place within an organism to sustain life, including processes such as breaking down molecules, building new molecules, and energy production. Choice A is incorrect because it describes excretion rather than metabolism. Choice B is incorrect as it specifically refers to the breakdown of substances, not encompassing the entirety of metabolic processes. Choice C is incorrect as it focuses solely on nutrient intake, which is just one aspect of metabolism.

4. Maintaining a stable internal environment typically requires

• A. positive feedback mechanisms.
• B. an unstable outside environment.
• C. decreased atmospheric pressure.
• D. negative feedback mechanisms.

Correct answer: D

Rationale: The correct answer is 'negative feedback mechanisms.' In biological systems, negative feedback mechanisms help maintain homeostasis by counteracting any deviations from the set point. They work to stabilize internal conditions and keep them within a narrow range. On the other hand, positive feedback mechanisms amplify changes and are not involved in maintaining stability. Choice B, 'an unstable outside environment,' is incorrect as internal stability is independent of external conditions like weather. Choice C, 'decreased atmospheric pressure,' is also incorrect as it does not directly relate to internal homeostasis.

5. Blood cells are produced in the organs of the _______ system.

• A. endocrine
• B. skeletal
• C. superior to
• D. inferior to

Correct answer: C

Rationale: Blood cells are produced in the organs of the hematopoietic system. The correct answer is 'superior to' as this refers to the location of the organs responsible for blood cell production, typically bone marrow found in bones such as the vertebrae, ribs, and skull. 'Endocrine' (Choice A) refers to a different system responsible for hormone production. 'Skeletal' (Choice B) relates to bones but not specifically to the production of blood cells. Choices C and D, 'superior to' and 'inferior to,' do not make sense in the context of blood cell production and are incorrect.

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