Nursing Elites

1. Which of the following basic mechanisms of evolution is described as the process where organisms with an advantageous trait survive more often and produce more offspring than organisms without the advantageous trait?

• A. gene flow
• B. genetic drift
• C. mutation
• D. natural selection

Correct answer: D

Rationale: Natural selection is the basic mechanism of evolution that explains how organisms with advantageous traits are more likely to survive and reproduce in a given environment. This leads to the passing on of these favorable traits to their offspring, causing these traits to become more common in the population over time, resulting in evolutionary change. Natural selection is driven by environmental pressures that support the survival and reproduction of individuals with specific traits. Gene flow refers to the movement of genes between populations, genetic drift is the change in allele frequencies due to random events, and mutation is the source of genetic variation but is not the process by which advantageous traits become more prevalent in a population.

2. What is the main component of stomach acid?

• A. Hydrochloric acid
• B. Bicarbonate
• C. Bile salts
• D. Enzymes

Correct answer: A

Rationale: Stomach acid, also known as gastric acid, is primarily composed of hydrochloric acid. Hydrochloric acid plays a crucial role in the digestive process by helping to break down food and kill bacteria in the stomach. Bicarbonate is a base that helps neutralize stomach acid in the small intestine, but it is not the main component of stomach acid. Bile salts are produced by the liver and stored in the gallbladder, aiding in the digestion and absorption of fats, but they are not the main component of stomach acid. Enzymes are proteins that help catalyze chemical reactions in the body, including the breakdown of food molecules during digestion, but they are not the main component of stomach acid.

3. Which division of the peripheral nervous system is responsible for transmitting signals from the central nervous system to skeletal muscles, enabling voluntary muscle movements?

• A. Somatic nervous system
• B. Autonomic nervous system
• C. Sympathetic nervous system
• D. Parasympathetic nervous system

Correct answer: A

Rationale: The correct answer is the somatic nervous system. The somatic nervous system is responsible for transmitting signals from the central nervous system to skeletal muscles, allowing for voluntary muscle movements. The autonomic nervous system, sympathetic nervous system, and parasympathetic nervous system are not involved in voluntary muscle movements. Instead, they regulate involuntary functions of the body such as heart rate, digestion, and breathing. Therefore, choices B, C, and D are incorrect as they are not associated with voluntary muscle movements.

4. Which of the following are functions of the urinary system?

• A. I, II, and III
• B. II and III
• C. II, III, and IV
• D. All of the above

Correct answer: D

Rationale: The corrected answer is D, 'All of the above.' The urinary system performs multiple essential functions to maintain the body's internal environment. Synthesizing calcitriol and secreting erythropoietin are crucial roles of the kidneys. Regulating the concentrations of sodium, potassium, chloride, calcium, and other ions helps in maintaining the electrolyte balance. Reabsorbing or secreting hydrogen ions and bicarbonate is vital for managing the body's acid-base balance. Furthermore, the urinary system is involved in detecting reductions in blood volume and pressure, aiding in the maintenance of blood pressure levels and fluid balance in the body.

5. What is the difference between isometric and isotonic muscle contractions?

• A. Isometric involves movement, while isotonic does not.
• B. Isotonic involves shortening of muscle, while isometric maintains length.
• C. Isometric uses more energy, while isotonic uses less.
• D. Isotonic involves smooth muscle, while isometric involves skeletal muscle.

Correct answer: B

Rationale: The correct answer is B. Isometric contractions occur when the muscle generates tension without changing its length, while isotonic contractions involve the muscle changing length to move a load. In isotonic contractions, the muscle shortens to move a load, whereas in isometric contractions, the muscle contracts to hold a position without movement. Choice A is incorrect because isometric contractions do not involve movement, while choice C is incorrect as isotonic contractions typically require more energy due to movement. Choice D is incorrect because the type of muscle involved (smooth or skeletal) is not the defining factor between isometric and isotonic contractions.

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