Nursing Elites

1. Which of the following functions is NOT performed by the integumentary system, the skin?

• A. Protect internal tissues from injury
• B. Waterproof the body
• C. Help regulate body temperature
• D. Return fluid to the blood vessels

Correct answer: D

Rationale: The integumentary system, which includes the skin, performs various functions like protecting internal tissues from injury, waterproofing the body, and helping regulate body temperature. The function of returning fluid to the blood vessels is primarily associated with the lymphatic system, not the integumentary system. The skin contributes to fluid balance by regulating sweating and preventing excessive water loss, but it does not directly return fluid to the blood vessels, making this the correct answer. Choices A, B, and C are functions directly related to the integumentary system and are essential for maintaining the body's overall health and well-being.

2. What type of lens is thinner at the center than at the edges and causes light rays to diverge?

• A. Convex lens
• B. Concave lens
• C. Diverging lens
• D. Plano-convex lens

Correct answer: B

Rationale: A concave lens is thinner at the center than at the edges, causing light rays to diverge when passing through it. This type of lens is also known as a diverging lens because it causes light rays to spread out. Concave lenses are used in various optical devices to correct vision problems and in scientific instruments to diverge light rays for specific purposes. The other choices are incorrect. A convex lens is thicker at the center and converges light rays, while a plano-convex lens has one flat surface and one convex surface, converging light. Diverging lens is a general term that can refer to concave or plano-concave lenses, but in this context, the specific type being referred to is a concave lens.

3. Which of the following is specialized tissue in the right atrium that acts as the heart’s natural pacemaker by generating the electrical signal for the heartbeat?

• A. sinus venosus
• B. sinoatrial node
• C. atrioventricular node
• D. tricuspid valve

Correct answer: B

Rationale: The sinoatrial node, often referred to as the SA node, is specialized tissue located in the right atrium of the heart. It functions as the heart's natural pacemaker by generating the electrical signal that initiates each heartbeat. This electrical signal spreads to the atrial muscles and then to the atrioventricular node, causing the heart to contract rhythmically and efficiently. The other options listed do not serve as the heart's natural pacemaker responsible for generating the electrical signal for the heartbeat. Sinus venosus is a developmental structure in fetal hearts, the atrioventricular node delays the electrical signal, and the tricuspid valve is a heart valve that prevents backflow of blood from the right ventricle to the right atrium.

4. What is the main function of the gallbladder?

• A. To store and concentrate bile
• B. To produce digestive enzymes
• C. To absorb nutrients
• D. To neutralize stomach acid

Correct answer: A

Rationale: The gallbladder is a small organ located beneath the liver that plays a crucial role in the digestive system. Its main function is to store and concentrate bile, a digestive fluid produced by the liver. Bile is released from the gallbladder into the small intestine to help with the digestion and absorption of fats. The gallbladder acts as a reservoir for bile, allowing it to be released in a controlled manner when needed to aid in the digestion of fatty foods. Option A is the correct answer as it accurately describes the main function of the gallbladder. Choices B, C, and D are incorrect because the gallbladder does not produce digestive enzymes, absorb nutrients, or neutralize stomach acid. These functions are carried out by other organs in the digestive system, such as the pancreas, small intestine, and stomach, respectively.

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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