Nursing Elites

1. Which muscular pouch in the upper left abdomen stores food after swallowing and begins mechanical and chemical digestion?

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

Correct answer: B

Rationale: The correct answer is B: Stomach. The stomach is the muscular pouch in the upper left abdomen that stores food after swallowing and begins mechanical and chemical digestion. It secretes gastric juices containing enzymes and hydrochloric acid to break down food particles. The esophagus is a muscular tube that carries food from the mouth to the stomach, while the small intestine and large intestine are primarily involved in the absorption of nutrients and water, respectively. Therefore, the stomach is the organ responsible for the described functions, making it the correct answer in this context.

2. What is the main function of calcitonin, a hormone produced by the thyroid gland?

• A. Stimulate metabolism and heat production
• B. Increase calcium absorption from the intestines
• C. Enhance bone growth and development
• D. Lower blood calcium levels

Correct answer: D

Rationale: Calcitonin is a hormone produced by the thyroid gland that primarily functions to lower blood calcium levels. It achieves this by inhibiting bone breakdown and promoting calcium excretion by the kidneys. Therefore, the correct answer is D as it reflects the main role of calcitonin in calcium homeostasis. Choices A, B, and C are incorrect as they do not align with the primary function of calcitonin. Calcitonin does not stimulate metabolism and heat production (Choice A), increase calcium absorption from the intestines (Choice B), or enhance bone growth and development (Choice C).

3. What causes dandruff?

• A. Excessive sebum production (This can contribute to oily dandruff)
• B. Bacterial infection (This can cause scalp folliculitis, not dandruff)
• C. Overgrowth of a specific type of fungus on the scalp
• D. Lack of proper skin hydration

Correct answer: C

Rationale: Dandruff is primarily caused by an overgrowth of a specific type of fungus called Malassezia on the scalp. This fungus feeds on the natural oils produced by the hair follicles, leading to irritation and flaking of the scalp skin. Choice A is incorrect because excessive sebum production can contribute to oily dandruff, but it is not the primary cause of dandruff. Choice B is incorrect as bacterial infection primarily causes scalp folliculitis, not dandruff. Choice D is incorrect as dandruff is not primarily caused by a lack of proper skin hydration.

4. What checkpoint mechanism ensures all chromosomes are attached to the spindle fibers before anaphase begins?

• A. Prometaphase
• B. Metaphase
• C. Cyclin degradation
• D. Sister chromatid cohesion

Correct answer: A

Rationale: A) Prometaphase is the correct answer because it is the stage of mitosis where all chromosomes are attached to the spindle fibers before anaphase begins. During prometaphase, the nuclear envelope breaks down, allowing the spindle fibers to attach to the kinetochores of the chromosomes. This attachment is necessary for proper chromosome alignment and segregation during anaphase. B) Metaphase is incorrect because it is the stage where chromosomes are aligned at the metaphase plate but do not necessarily have all spindle fibers attached. C) Cyclin degradation is incorrect because it is a regulatory mechanism that controls the progression of the cell cycle but is not specifically related to ensuring all chromosomes are attached to spindle fibers. D) Sister chromatid cohesion is incorrect because it refers to the physical connection between sister chromatids that is maintained until anaphase, but it does not ensure that all chromosomes are attached to spindle fibers.

5. What potential consequences can chromosomal nondisjunction have on offspring?

• A. Down syndrome, caused by an extra copy of chromosome 21.
• B. Turner syndrome, characterized by the absence of one X chromosome in females.
• C. Klinefelter syndrome, featuring one or more extra X chromosomes in males.
• D. All of the above.

Correct answer: D

Rationale: - Chromosomal nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division, leading to an abnormal number of chromosomes in the resulting cells. - Down syndrome is caused by an extra copy of chromosome 21, resulting from nondisjunction during meiosis. Individuals with Down syndrome have three copies of chromosome 21 instead of the usual two. - Turner syndrome is characterized by the absence of one X chromosome in females, leading to a variety of physical and developmental features. - Klinefelter syndrome features one or more extra X chromosomes in males, typically resulting in infertility and other physical characteristics. Therefore, chromosomal nondisjunction can lead to various genetic disorders such as Down syndrome, Turner syndrome, and Klinefelter syndrome, making option D the correct answer.

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