Nursing Elites

1. Which type of immunity does the MMR vaccine provide?

• A. Artificial/active
• B. Artificial/passive
• C. Natural/active
• D. Natural/passive

Correct answer: A

Rationale: The correct answer is A: Artificial/active. The MMR vaccine provides artificial/active immunity. It works by introducing a weakened or killed form of the virus to trigger the body's immune response, leading to the production of antibodies that offer long-lasting protection against measles, mumps, and rubella. Artificial immunity is obtained through medical intervention, such as vaccination, while active immunity involves the immune system's direct response to an antigen. Choices B, C, and D are incorrect because the MMR vaccine does not provide passive immunity nor is it acquired naturally; instead, it stimulates the body to actively produce its immune response.

2. What potential consequences can chromosomal nondisjunction have on offspring?

• A. Down syndrome, caused by an extra copy of chromosome 21.
• B. Turner syndrome, characterized by the absence of one X chromosome in females.
• C. Klinefelter syndrome, featuring one or more extra X chromosomes in males.
• D. All of the above.

Correct answer: D

Rationale: - Chromosomal nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division, leading to an abnormal number of chromosomes in the resulting cells. - Down syndrome is caused by an extra copy of chromosome 21, resulting from nondisjunction during meiosis. Individuals with Down syndrome have three copies of chromosome 21 instead of the usual two. - Turner syndrome is characterized by the absence of one X chromosome in females, leading to a variety of physical and developmental features. - Klinefelter syndrome features one or more extra X chromosomes in males, typically resulting in infertility and other physical characteristics. Therefore, chromosomal nondisjunction can lead to various genetic disorders such as Down syndrome, Turner syndrome, and Klinefelter syndrome, making option D the correct answer.

3. What is the function of arrector pili muscles?

• A. To control sweat production
• B. To contract and cause goosebumps
• C. To produce sebum
• D. To sense touch

Correct answer: B

Rationale: The correct function of arrector pili muscles is to contract and cause goosebumps. These small muscles are attached to hair follicles in mammals. When they contract, they cause the hair to stand on end, resulting in goosebumps. This physiological response is often triggered by cold temperatures or emotional states like fear, helping mammals conserve heat or appear larger in threatening situations. Choices A, C, and D are incorrect. Arrector pili muscles are not involved in controlling sweat production (Choice A), producing sebum (Choice C), or sensing touch (Choice D).

4. The number of protons in an atom determines its:

• A. Mass number
• B. Atomic number
• C. Atomic weight
• D. Valence electron count

Correct answer: B

Rationale: The number of protons in an atom is known as the atomic number. The atomic number uniquely identifies an element and determines its position on the periodic table. It is a fundamental property of an element and directly influences its chemical behavior and interactions. The mass number, on the other hand, is the sum of protons and neutrons in the nucleus of an atom, not just protons. Atomic weight is the average mass of an element's isotopes considering their relative abundance, not solely based on the number of protons. Valence electron count refers to the number of electrons in the outermost energy level of an atom, influencing its ability to form bonds and participate in chemical reactions, but it is not determined by the number of protons in the atom.

5. What is the function of the myelin sheath in a neuron?

• A. To transmit electrical impulses
• B. To insulate and speed up electrical signals
• C. To produce neurotransmitters
• D. To protect the neuron from damage

Correct answer: B

Rationale: The myelin sheath serves to insulate neurons and accelerate the transmission of electrical signals along the axon. This insulation helps in the efficient conduction of nerve impulses by preventing signal loss or leakage. Choice A is incorrect because the myelin sheath does not transmit electrical impulses itself but rather helps in the conduction. Choice C is incorrect as the myelin sheath is not responsible for producing neurotransmitters. Choice D is also incorrect as the primary function of the myelin sheath is not to protect the neuron from damage. Therefore, the correct answer is B, as it accurately describes the function of the myelin sheath in a neuron.

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