Nursing Elites

1. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

• A. Aortic valve
• B. Pulmonary valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: D

Rationale: The correct answer is D, the Mitral valve. The mitral valve, also known as the bicuspid valve, is situated between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The other choices are incorrect because: A) The aortic valve prevents backflow from the aorta into the left ventricle. B) The pulmonary valve prevents backflow from the pulmonary artery into the right ventricle. C) The tricuspid valve prevents backflow from the right ventricle into the right atrium.

2. What is the role of the pancreas in digestion?

• A. To secrete bile
• B. To secrete digestive enzymes
• C. To absorb nutrients
• D. To transport waste

Correct answer: B

Rationale: The correct answer is B: 'To secrete digestive enzymes.' The pancreas plays a crucial role in digestion by secreting digestive enzymes that break down carbohydrates, proteins, and fats. This process aids in the breakdown of food into nutrients that can be absorbed by the small intestine. Choices A, C, and D are incorrect because the pancreas is not responsible for secreting bile (liver and gallbladder function), absorbing nutrients (small intestine function), or transporting waste (colon function) in the digestive system.

3. Homologous structures are similar structures in different organisms that have a common evolutionary origin. An example is:

• A. Butterfly wings and bird wings (analogous structures with different origins)
• B. The arm of a human, the wing of a bat, and the flipper of a whale
• C. The eyes of an octopus and a human (convergent evolution with different origins)
• D. The stinger of a bee and the barb of a cactus (unrelated structures)

Correct answer: B

Rationale: Homologous structures are similar structures found in different organisms that share a common evolutionary origin. The arm of a human, the wing of a bat, and the flipper of a whale are all examples of homologous structures. Despite serving different functions, they share a common underlying structure due to their evolutionary relationship, evidencing a shared ancestry. These structures are modified over time to suit the specific needs of each species. Option A (Butterfly wings and bird wings) refers to analogous structures with different origins. Option C (The eyes of an octopus and a human) describes convergent evolution where traits evolve independently. Option D (The stinger of a bee and the barb of a cactus) are unrelated structures.

4. What is the basic structural and functional unit of the kidney?

• A. Neuron
• B. Nephron
• C. Glomerulus
• D. Axon

Correct answer: B

Rationale: The correct answer is B, Nephron. The nephron is indeed the basic structural and functional unit of the kidney. It is responsible for filtering blood, regulating electrolytes, maintaining fluid balance, and removing waste products. Choice A, Neuron, is incorrect as neurons are nerve cells, not specific to kidney function. Choice C, Glomerulus, is a component of the nephron but not the entire functional unit. Choice D, Axon, is a part of nerve cells and is not related to kidney structure or function.

5. What is the general formula for an alcohol?

• A. CₙH₂ₙ
• B. CₙH₂ₙ₊₂
• C. CₙH₂ₙ₋₁
• D. CₙH₂ₙO

Correct answer: D

Rationale: The correct general formula for an alcohol is CnH2n+1OH, which can be simplified to CnH2nO. In this formula, 'n' represents the number of carbon atoms, '2n' represents the number of hydrogen atoms, and 'O' represents the oxygen atom present in the hydroxyl group of the alcohol. Therefore, the correct general formula for an alcohol is CnH2nO. Choice A, CₙH₂ₙ, does not account for the oxygen atom, which is essential in alcohols. Choice B, CₙH₂ₙ₊₂, does not include the oxygen atom or the necessary hydrogen atoms for the hydroxyl group. Choice C, CₙH₂ₙ₋₁, lacks the oxygen atom and also does not fulfill the requirements of the hydroxyl group. Thus, the most accurate representation of the general formula for an alcohol is CnH2nO.

Similar Questions