Nursing Elites

1. What is the primary function of the pyloric sphincter?

• A. to regulate the movement of food material from the stomach to the duodenum
• B. to neutralize stomach acid
• C. to prevent digested food materials and stomach acid from entering the esophagus
• D. to begin the process of chemical digestion

Correct answer: A

Rationale: The primary function of the pyloric sphincter is to regulate the flow of partially digested food material (chyme) from the stomach into the small intestine, specifically the duodenum. This control is essential for proper digestion and absorption of nutrients in the small intestine. Choices B, C, and D are incorrect. Choice B is incorrect because neutralizing stomach acid is primarily the function of the stomach lining and antacid mechanisms. Choice C is incorrect because preventing the backflow of digested food materials and stomach acid into the esophagus is mainly the role of the lower esophageal sphincter. Choice D is incorrect because the chemical digestion process primarily starts in the stomach through the action of gastric juices, not the pyloric sphincter.

2. An atom has 2 protons, 4 neutrons, and 2 electrons. What is the approximate atomic mass of this atom?

• A. 2
• B. 4
• C. 6
• D. 8

Correct answer: D

Rationale: The atomic mass of an atom is the sum of the protons and neutrons in its nucleus. In this case, the atom has 2 protons and 4 neutrons, totaling 6 particles in the nucleus. Therefore, the approximate atomic mass of this atom is 6, making choice C incorrect. The number of electrons does not significantly contribute to the atomic mass, as they are much lighter and located in the electron cloud surrounding the nucleus. Choices A, B, and C are incorrect as they do not reflect the correct calculation of atomic mass based on protons and neutrons only.

3. Which hormone plays a key role in stimulating the release of milk from breast tissue after childbirth?

• A. Follicle-stimulating hormone (FSH)
• B. Luteinizing hormone (LH)
• C. Prolactin
• D. Estrogen

Correct answer: C

Rationale: Prolactin is the hormone responsible for stimulating the release of milk from breast tissue after childbirth. It is produced by the pituitary gland and plays a crucial role in lactation. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are involved in the menstrual cycle and reproductive processes, not milk production. Estrogen is a female sex hormone with various functions but is not directly involved in milk production.

4. Which structure do cells rely on for movement?

• A. Flagellum
• B. Microtubule
• C. Pili
• D. Vesicle

Correct answer: A

Rationale: The correct answer is A: Flagellum. Cells rely on flagella for movement, which are whip-like structures that propel the cell forward through their whipping motion. Flagella provide motility to single-celled organisms and certain cells in multicellular organisms. Microtubules, on the other hand, provide structural support to the cell and play a role in intracellular transport. Pili are short, hair-like structures used for attachment to surfaces or other cells, not for movement. Vesicles are membrane-bound sacs involved in intracellular transport, aiding in the movement of substances within the cell, but not in the movement of the cell itself.

5. Which two types of elements are most likely to form an ionic bond?

• A. Two elements that are in the same period.
• B. Two elements that are non-metals and have p orbitals.
• C. One element that is a transition metal with d orbitals and one element that is a metal with s orbitals.
• D. One element that is a metal with s orbitals and one element that is a nonmetal with p orbitals.

Correct answer: D

Rationale: Ionic bonds typically form between a metal, which donates electrons from its s orbital, and a nonmetal, which accepts electrons into its p orbital. This transfer of electrons leads to the formation of an ionic bond. Choice A is incorrect as elements in the same period may vary significantly in their properties. Choice B is incorrect because ionic bonds are usually formed between a metal and a nonmetal, not two nonmetals. Choice C is incorrect because transition metals generally form complex ions through the sharing of electrons, not typical ionic bonds.

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