Nursing Elites

1. Which layer of the skin is responsible for new skin cell production?

• A. Stratum corneum
• B. Stratum basale
• C. Stratum granulosum
• D. Stratum spinosum

Correct answer: B

Rationale: The correct answer is B, Stratum basale. The stratum basale, also known as the basal layer or stratum germinativum, is the deepest layer of the epidermis and is responsible for new skin cell production through cell division. It contains basal cells that continuously divide to produce new keratinocytes, which move up through the layers of the epidermis. Choice A, Stratum corneum, is the outermost layer of the epidermis consisting of dead cells filled with keratin. It serves a protective function but is not involved in new skin cell production. Choice C, Stratum granulosum, is a layer of the epidermis where keratinocytes undergo changes in their structure and composition. It is involved in the process of keratinization but not in new skin cell production. Choice D, Stratum spinosum, is a layer of the epidermis where cells become interconnected by desmosomes. While it plays a role in providing strength and support to the epidermis, it is not primarily responsible for new skin cell production.

2. Where does visual processing begin in the eye?

• A. Cornea
• B. Optic nerve
• C. Retina
• D. Eyelid

Correct answer: C

Rationale: Visual processing begins in the retina, not the cornea, optic nerve, or eyelid. The retina is a layer of tissue at the back of the eye that contains photoreceptor cells responsible for converting light into neural signals that are then sent to the brain for processing. The cornea is the transparent outer layer of the eye that helps focus light, but it does not process visual information. The optic nerve transmits visual information from the retina to the brain, it does not initiate visual processing. The eyelid is a protective covering for the eye and is not involved in visual processing.

3. Which of the following produces the first heart sound ('lub')?

• A. The closing of the aortic and pulmonary valves
• B. The closing of the tricuspid and mitral valves
• C. The opening of the aortic and pulmonary valves
• D. The opening of the tricuspid and mitral valves

Correct answer: B

Rationale: The correct answer is B. The first heart sound, known as the 'lub' sound, is produced by the closure of the tricuspid and mitral valves, which are the atrioventricular valves. This sound marks the beginning of systole in the cardiac cycle. Choice A, the closing of the aortic and pulmonary valves, is incorrect as these valves produce the second heart sound ('dub'). Choice C, the opening of the aortic and pulmonary valves, is incorrect because the first heart sound occurs during ventricular contraction (systole). Choice D, the opening of the tricuspid and mitral valves, is incorrect as the 'lub' sound is associated with the closure, not the opening, of these valves.

4. Which element has the same number of protons and neutrons?

• A. Carbon (C)
• B. Oxygen (O)
• C. Lithium (Li)
• D. Helium (He)

Correct answer: D

Rationale: The correct answer is Helium (He). Helium has an atomic number of 2, meaning it has 2 protons. It also has 2 neutrons, which gives it a total mass number of 4. Therefore, Helium is an example of an element with an equal number of protons and neutrons. Choice A (Carbon) has 6 protons and usually has more neutrons than protons. Choice B (Oxygen) has 8 protons and 8 neutrons, so the numbers are not equal. Choice C (Lithium) has 3 protons and usually has more neutrons than protons, so it does not fit the criteria of having the same number of protons and neutrons.

5. How many chromosomes must a normal human sperm cell contain?

• A. An X chromosome.
• B. A Y chromosome.
• C. 23 chromosomes.
• D. Both an X and Y chromosome.

Correct answer: C

Rationale: A normal human sperm cell contains a total of 23 chromosomes, half the number found in a typical human cell which has 46 chromosomes. This includes 22 autosomes and one sex chromosome, which can be either an X or a Y chromosome. Therefore, the correct answer is that a normal human sperm cell must contain 23 chromosomes. Choices A and B are incorrect because a single sex chromosome alone does not represent the total number of chromosomes in a sperm cell. Choice D is incorrect because a sperm cell carries only one sex chromosome, either X or Y, not both.

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