Nursing Elites

1. Which of the following touch receptors respond to light touch and slower vibrations?

• A. Merkel's discs
• B. Pacinian corpuscles
• C. Meissner's corpuscles
• D. Ruffini endings

Correct answer: A

Rationale: The correct answer is A, Merkel's discs. Merkel's discs are touch receptors that respond to light touch and slower vibrations, making them ideal for detecting subtle tactile stimuli. Pacinian corpuscles are specialized in detecting deep pressure and high-frequency vibrations, not light touch or slower vibrations. Meissner's corpuscles, on the other hand, are sensitive to light touch and low-frequency vibrations, but they do not specifically respond to slower vibrations. Ruffini endings are responsible for detecting skin stretch and continuous touch pressure, differentiating them from Merkel's discs, which are specifically attuned to light touch and slower vibrations.

2. What is the term for the involuntary muscle contractions that move food through the digestive tract?

• A. Segmentation
• B. Peristalsis
• C. Chyme
• D. Emulsification

Correct answer: B

Rationale: Peristalsis is the correct term for the involuntary muscle contractions that move food through the digestive tract. These contractions help push food along the digestive system, facilitating digestion and absorption of nutrients. Segmentation, on the other hand, refers to the mixing and breaking down of food in the intestines, not the movement of food. Chyme is the semi-fluid mass of partially digested food in the stomach and small intestine, not the muscle contractions. Emulsification is the process of breaking down fat globules into smaller droplets to aid in digestion, not the movement of food through the digestive tract. Therefore, peristalsis is the most appropriate term for this function.

3. The small intestine is where most of the chemical digestion and nutrient absorption occur. What is the finger-like projection in the small intestine that increases its surface area for absorption?

• A. Rugae
• B. Villi
• C. Microvilli
• D. All of the above

Correct answer: C

Rationale: Microvilli are the finger-like projections in the small intestine that increase its surface area for absorption. Villi are also present in the small intestine and help increase the surface area for absorption. However, microvilli are smaller structures found on the surface of villi, further increasing the surface area available for nutrient absorption. Rugae are folds in the stomach that allow for expansion when food is consumed and are not found in the small intestine. Therefore, the correct answer is C) Microvilli. Villi and microvilli are specific to the small intestine, playing vital roles in nutrient absorption, while rugae are specific to the stomach's structure and function, serving a different purpose than increasing surface area for absorption.

4. Which of the following statements is true regarding a supersaturated solution?

• A. It is unstable and tends to crystallize
• B. It contains more solute than it could dissolve
• C. It has a higher concentration than a saturated solution
• D. It is rarely encountered in everyday solutions

Correct answer: A

Rationale: A supersaturated solution is unstable and tends to crystallize because it contains more solute than it could dissolve at a given temperature. This excess solute is in a metastable state and can precipitate out if disturbed, leading to the formation of crystals. Option B is incorrect because a supersaturated solution does contain more solute than it could normally dissolve, but it becomes unstable due to this excess solute. Option C is incorrect because while a supersaturated solution does have a higher concentration than a saturated solution, the defining characteristic related to its instability is the excess solute. Option D is incorrect as supersaturated solutions can be encountered in various everyday scenarios, such as certain sugar solutions used in cooking or rock candy production.

5. Which statement about white blood cells is true?

• A. B cells are responsible for antibody production.
• B. White blood cells are produced in the bone marrow before entering the bloodstream.
• C. Platelets, a specialized class of blood cells, function to clot blood and stop bleeding.
• D. The majority of white blood cells are active throughout life, providing immunity across all age groups.

Correct answer: A

Rationale: The correct answer is A: B cells, a type of white blood cell, are responsible for producing antibodies in response to pathogens. Antibodies play a crucial role in identifying and neutralizing foreign substances like bacteria and viruses in the body, aiding in the immune response and protecting against infections. This function is essential for maintaining a healthy immune system. White blood cells, including B cells, are produced in the bone marrow before entering the bloodstream. Platelets, not white blood cells, are a specialized class of blood cells that function to clot blood and stop bleeding. While white blood cells provide immunity, not all of them are active throughout life as some have specific lifespans and functions.

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