Nursing Elites

1. What is the purpose of sodium bicarbonate when released into the lumen of the small intestine?

• A. It works to chemically digest fats in the chyme.
• B. It decreases the pH of the chyme to prevent harm to the intestine.
• C. It works to chemically digest proteins in the chyme.
• D. It increases the pH of the chyme to prevent harm to the intestine.

Correct answer: D

Rationale: Sodium bicarbonate, when released into the lumen of the small intestine, functions to increase the pH of the acidic chyme coming from the stomach. This increase in pH helps neutralize the acidity of the chyme, creating a more optimal environment for the digestive enzymes in the small intestine to function properly. Maintaining a slightly basic pH in the small intestine is crucial for overall digestion and absorption of nutrients. Choices A, B, and C are incorrect. Sodium bicarbonate does not chemically digest fats or proteins in the chyme, and it does not decrease the pH of the chyme as it actually increases the pH to prevent harm to the intestine.

2. Which type of joint allows for the greatest range of motion?

• A. Hinge joint
• B. Ball-and-socket joint
• C. Pivot joint
• D. Saddle joint

Correct answer: B

Rationale: The correct answer is B: Ball-and-socket joint. The ball-and-socket joint, like the shoulder joint, allows for the greatest range of motion due to its structure, enabling movement in multiple directions. In contrast, hinge joints, pivot joints, and saddle joints have more restricted ranges of motion compared to ball-and-socket joints. Hinge joints primarily allow movement in one plane, pivot joints allow rotation around a central axis, and saddle joints have limited movement compared to ball-and-socket joints.

3. What is the role of RNA interference in silencing genes?

• A. Increases protein production
• B. Promotes gene mutation
• C. Inhibits the expression of specific genes
• D. Repairs damaged DNA

Correct answer: C

Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, 'Inhibits the expression of specific genes,' is the correct role of RNA interference in silencing genes. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.

4. Testosterone is a crucial hormone in the male reproductive system. What is its primary function?

• A. Egg production
• B. Sperm production and development
• C. Regulation of the menstrual cycle
• D. Milk production

Correct answer: B

Rationale: Testosterone is a hormone primarily produced in the testes of males and is responsible for the development of male reproductive tissues, including the testes and prostate. Its primary function is the production and maturation of sperm cells, as well as the development of secondary sexual characteristics in males. Choice A, 'Egg production,' is incorrect as testosterone is not involved in the production of eggs. Choice C, 'Regulation of the menstrual cycle,' is incorrect because testosterone is not responsible for regulating the menstrual cycle, which is primarily governed by female hormones. Choice D, 'Milk production,' is incorrect as testosterone does not play a role in milk production, which is associated with other hormones like prolactin in females.

5. Which type of cells make up the myelin sheaths?

• A. Glial cells.
• B. Dendrites.
• C. Melanocytes.
• D. Squamous cells.

Correct answer: A

Rationale: The correct answer is A: Glial cells. Glial cells are responsible for producing the myelin sheaths that surround and insulate nerve cells in the central and peripheral nervous systems. Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system are types of glial cells that form the myelin sheaths. Choice B, dendrites, are not involved in forming myelin sheaths; they are extensions of neurons that receive signals. Choice C, melanocytes, are cells responsible for producing melanin, not myelin. Choice D, squamous cells, are flat epithelial cells found in various tissues but are not involved in myelin sheath formation.

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