Nursing Elites

1. During normal breathing, which muscle is the primary driver of inhalation by contracting and flattening to increase the volume of the thoracic cavity?

• A. Diaphragm
• B. Intercostal muscles
• C. Abdominal muscles
• D. Pectoral muscles

Correct answer: A

Rationale: The diaphragm is the primary muscle responsible for inhalation during normal breathing. When it contracts, it flattens, increasing the volume of the thoracic cavity and creating a negative pressure that allows air to flow into the lungs. Intercostal muscles also play a role in expanding the chest cavity during inhalation, but the diaphragm is the main driver of the process. Abdominal muscles are primarily involved in exhalation by pushing the diaphragm upward to expel air from the lungs. Pectoral muscles are involved in movements of the arms and shoulders, not in breathing, making them incorrect choices for this question.

2. In a balanced chemical equation, the coefficients represent the:

• A. Number of elements
• B. Ratio of reactants and products
• C. Physical state of the substances
• D. Rate of the reaction

Correct answer: A

Rationale: The correct answer is A: 'Number of elements.' In a balanced chemical equation, coefficients represent the ratio of moles of each species involved in the reaction. They indicate the relative number of molecules or formula units of each compound taking part in the reaction. Choice B, 'Ratio of reactants and products,' is incorrect because the coefficients in a balanced equation do not represent the ratio of reactants and products directly, but rather the stoichiometry of the reaction. Choice C, 'Physical state of the substances,' is incorrect because the physical states (solid, liquid, gas, or aqueous) are denoted with symbols next to the chemical formula, not the coefficients. Choice D, 'Rate of the reaction,' is incorrect as coefficients in a balanced equation do not provide information about the rate of the reaction, which is determined by factors like temperature, concentration, and catalysts.

3. What is involved in the involuntary reflex arc that withdraws your hand from a hot object?

• A. Central nervous system only
• B. Peripheral nervous system only
• C. Both CNS and PNS
• D. Sensory neurons only

Correct answer: C

Rationale: The involuntary reflex arc that withdraws your hand from a hot object involves both the central nervous system (CNS) and the peripheral nervous system (PNS). When your hand touches a hot object, sensory neurons in the PNS detect the heat and send signals to the spinal cord in the CNS. The spinal cord processes this information and sends a signal back through motor neurons in the PNS to move your hand away from the hot object. This coordinated response requires the collaboration of both the CNS and PNS to protect the body from harm. Choice A is incorrect because the reflex arc involves more than just the central nervous system. Choice B is incorrect because the reflex arc involves more than just the peripheral nervous system. Choice D is incorrect because the reflex arc also involves motor neurons, not just sensory neurons.

4. Through which part of the digestive system are nutrients absorbed into the bloodstream?

• A. Stomach
• B. Large intestine
• C. Small intestine
• D. Esophagus

Correct answer: C

Rationale: The small intestine is the primary site of nutrient absorption in the digestive system. It is where the majority of digestion and absorption of nutrients such as carbohydrates, proteins, and fats occurs. The inner lining of the small intestine is covered in tiny finger-like projections called villi, which increase the surface area available for absorption. Nutrients are absorbed through the walls of the small intestine and into the bloodstream to be transported to cells throughout the body. The stomach's main role is to break down food through the action of stomach acids and enzymes but does not absorb nutrients. The large intestine primarily absorbs water and electrolytes from the remaining indigestible food matter, and the esophagus is a muscular tube that transports food from the mouth to the stomach, without being involved in nutrient absorption.

5. Which of the following factors would NOT affect the solubility of a solid solute in a liquid solvent?

• A. Temperature
• B. Pressure
• C. Particle size
• D. Nature of the solute and solvent

Correct answer: B

Rationale: Pressure does not typically affect the solubility of a solid solute in a liquid solvent. Solubility is primarily influenced by factors such as temperature, particle size, and the nature of the solute and solvent. Increasing pressure generally has a minimal effect on the solubility of solids in liquids. The impact of pressure on solubility is more significant for gases in liquids rather than solids in liquids. Therefore, option B is the correct answer. Options A, C, and D directly impact the solubility of a solid solute in a liquid solvent. Temperature affects the solubility as it changes the kinetic energy of particles, particle size can impact the surface area available for interaction between solute and solvent, and the nature of the solute and solvent influences their intermolecular interactions and compatibility.

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