Nursing Elites

1. What is the electrical charge of the nucleus?

• A. A nucleus always has a positive charge.
• B. A stable nucleus has a positive charge, but a radioactive nucleus may have no charge and instead be neutral.
• C. A nucleus always has no charge and is instead neutral.
• D. A stable nucleus has no charge and is instead neutral, but a radioactive nucleus may have a charge.

Correct answer: A

Rationale: A nucleus always has a positive charge. This is because the nucleus is composed of positively charged protons, along with neutral neutrons. The positive charge of the protons is balanced by the negative charge of the surrounding electrons in an atom, resulting in an overall neutral charge for the atom as a whole. Therefore, choice A is correct as it accurately reflects the positive charge of the nucleus due to the presence of protons. Choices B, C, and D are incorrect because they do not accurately represent the fundamental composition and charge distribution within an atom's nucleus. A stable nucleus consists of positively charged protons and neutral neutrons, leading to an overall positive charge, and not a neutral charge as suggested in the incorrect choices.

2. Which of the following is NOT an example of a homeostatic mechanism?

• A. Shivering when the body temperature falls.
• B. Increasing heart rate when blood pressure is low.
• C. Weight gain when consuming excess calories.
• D. Secreting insulin to decrease blood sugar concentration.

Correct answer: C

Rationale: Weight gain when consuming excess calories is not an example of a homeostatic mechanism. Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. The other options listed (A, B, and D) involve physiological responses aimed at restoring balance or stability within the body (e.g., regulating body temperature, blood pressure, and blood sugar levels). Shivering, increasing heart rate, and secreting insulin are mechanisms to counteract specific imbalances and maintain internal equilibrium. In contrast, weight gain due to excess calorie intake does not represent a specific regulatory mechanism but rather an outcome of energy imbalance. The body stores excess energy as fat rather than actively regulating a physiological parameter to restore balance.

3. A 10 kg box rests on a frictionless surface. A horizontal force of 20 N is applied to the box. What is the box's acceleration?

• A. 0.5 m/s²
• B. 1 m/s²
• C. 2 m/s²
• D. 10 m/s²

Correct answer: B

Rationale: The acceleration of an object is given by the formula \(a = \frac{F}{m}\), where \(F\) is the net force acting on the object and \(m\) is the mass of the object. In this case, the net force acting on the box is 20 N, and the mass of the box is 10 kg. Plugging these values into the formula, we get \(a = \frac{20}{10} = 2\) m/s².

4. Which hormone, produced by the ovaries, is responsible for the development of the uterine lining during the menstrual cycle and supports early pregnancy?

• A. Estrogen
• B. Progesterone
• C. Testosterone
• D. Prolactin

Correct answer: B

Rationale: Progesterone, produced by the ovaries, is responsible for the development of the uterine lining during the menstrual cycle and supports early pregnancy. While estrogen also plays a crucial role in the menstrual cycle, progesterone is specifically known for its role in preparing the uterus for pregnancy and maintaining the uterine lining. Testosterone is primarily a male sex hormone and not directly involved in these processes. Prolactin is a hormone that is mainly associated with milk production and not related to the development of the uterine lining or early pregnancy.

5. When a muscle shortens and generates force, this is called a:

• A. Contraction
• B. Relaxation
• C. Extension
• D. Atrophy

Correct answer: A

Rationale: When a muscle shortens and generates force, it is contracting. Contraction is the process by which muscle fibers develop tension and exert a pulling force on the bones they are attached to, resulting in movement. Relaxation refers to the phase when a muscle returns to its original length, allowing for rest or preparation for the next contraction. Extension, on the other hand, is the movement that increases the angle between body parts, moving them further apart. Atrophy is unrelated to muscle contraction and refers to the wasting away or decrease in size of muscle tissue due to disuse or disease. Therefore, the correct answer is 'Contraction.'

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