Nursing Elites

1. What controls the involuntary, rhythmic contractions of the heart muscle?

• A. Lungs
• B. Brain
• C. Spinal cord
• D. Sinoatrial node (located within the heart)

Correct answer: D

Rationale: The correct answer is D: Sinoatrial node (located within the heart). The involuntary, rhythmic contractions of the heart muscle are controlled by a specialized group of cells located within the heart called the sinoatrial node (SA node). The SA node acts as the heart's natural pacemaker, producing electrical impulses that regulate the heart rate and synchronize the contractions of the heart muscle. Choices A, B, and C (Lungs, Brain, Spinal cord) are not responsible for directly influencing the rhythmic contractions of the heart muscle.

2. Which of the following is a pair of nerves that originates from the brain?

• A. Spinal nerves
• B. Olfactory nerves
• C. Sciatic nerve
• D. Optic nerve

Correct answer: B

Rationale: The olfactory nerves, choice B, are a pair of cranial nerves that originate from the brain. They are responsible for the sense of smell and are the only cranial nerves that directly connect to the cerebrum. Spinal nerves, choice A, originate from the spinal cord, the sciatic nerve, choice C, is a large nerve that originates in the lower back, and the optic nerve, choice D, originates from the retina of the eye. Therefore, choices A, C, and D are incorrect as they do not originate directly from the brain.

3. What is the energy required to break a chemical bond called?

• A. Kinetic energy
• B. Potential energy
• C. Activation energy
• D. Bond energy

Correct answer: C

Rationale: Activation energy is the energy required to break a chemical bond and initiate a chemical reaction. It is the minimum amount of energy needed to start a chemical reaction by breaking bonds in the reactant molecules. Kinetic energy (option A) is the energy of motion and is not directly related to breaking chemical bonds. Potential energy (option B) is stored energy that can be converted into other forms of energy but is not specifically about breaking chemical bonds. Bond energy (option D) refers to the energy required to break a particular chemical bond in a molecule and is not the general term for the energy needed to break any chemical bond. Activation energy is crucial in determining the rate of a chemical reaction as it affects the probability of reactant molecules colliding with sufficient energy to surpass the energy barrier and form products.

4. Which property of a substance refers to its ability to be hammered or pressed into thin sheets without breaking?

• A. Malleability
• B. Ductility
• C. Viscosity
• D. Conductivity

Correct answer: A

Rationale: Malleability is the correct answer as it is the property of a substance that allows it to be hammered or pressed into thin sheets without breaking. This property is crucial for materials like metals that need to be shaped without breaking. Ductility, on the other hand, refers to the ability of a substance to be drawn into thin wires, not hammered into sheets. Viscosity is a measure of a fluid's resistance to flow, indicating its thickness or thinness, and is unrelated to the ability to be hammered. Conductivity, on the other hand, refers to a substance's ability to conduct electricity or heat, which is not related to its ability to be hammered or pressed into thin sheets.

5. What is the process by which a solid changes directly into a liquid?

• A. Melting
• B. Condensation
• C. Sublimation
• D. Deposition

Correct answer: A

Rationale: The correct answer is A: Melting. Melting is the process through which a solid substance changes directly into a liquid. Choice B, Condensation, is the transition from gas to liquid. Choice C, Sublimation, refers to the direct change from solid to gas. Choice D, Deposition, is the direct transition from gas to solid, not from solid to liquid as in the question.

Similar Questions