Nursing Elites

1. What are the chemical messengers that control growth, differentiation, and metabolism of specific target cells called?

• A. Hormones
• B. Neurons
• C. Glands
• D. Second messengers

Correct answer: A

Rationale: Hormones are signaling molecules produced by glands in multicellular organisms. They travel through the bloodstream to specific target cells where they regulate various physiological processes, including growth, differentiation, and metabolism. Neurons (choice B) are nerve cells that transmit nerve impulses and are not responsible for controlling growth, differentiation, or metabolism. Glands (choice C) produce and release hormones but are not the chemical messengers themselves. Second messengers (choice D) are molecules involved in intracellular signal transduction, not the primary chemical messengers controlling growth, differentiation, and metabolism. Therefore, hormones (choice A) are the correct answer as they match the description provided in the question.

2. What is the primary hormone secreted by the thyroid gland?

• A. Oxytocin
• B. TSH
• C. Adrenaline
• D. T4

Correct answer: D

Rationale: The correct answer is D: T4. The primary hormone secreted by the thyroid gland is thyroxine, also known as T4. T4 plays a crucial role in regulating metabolism, growth, and energy levels in the body. It is converted into the more active form, triiodothyronine (T3), which exerts most of the biological effects of thyroid hormones. Choices A, B, and C are incorrect. Oxytocin is not produced by the thyroid gland but by the pituitary gland, TSH (thyroid-stimulating hormone) is secreted by the pituitary gland to stimulate the thyroid gland, and adrenaline is produced by the adrenal glands, not the thyroid gland.

3. Which part of the eye is responsible for color vision?

• A. Cornea
• B. Iris
• C. Retina
• D. Lens

Correct answer: C

Rationale: The correct answer is option C: Retina. The retina contains photoreceptor cells, including cones that are responsible for color vision. Cones are sensitive to different wavelengths of light, allowing us to perceive and differentiate various colors. Choice A, Cornea, is the transparent outer layer of the eye that helps focus light. It does not play a direct role in color vision. Choice B, Iris, is the colored part of the eye that controls the size of the pupil and regulates the amount of light entering the eye. While it is essential for adjusting light levels, it is not directly involved in color vision. Choice D, Lens, is responsible for focusing light onto the retina. It helps to form clear images on the retina but does not play a role in color vision.

4. Which type of muscle is found in the heart?

• A. Smooth muscle
• B. Cardiac muscle
• C. Skeletal muscle
• D. Striated muscle

Correct answer: B

Rationale: Cardiac muscle is a specialized type of muscle found only in the heart. It is responsible for the rhythmic contractions that pump blood throughout the body. Unlike smooth and skeletal muscle, cardiac muscle has its own unique structure and function to meet the demands of the heart's continuous pumping action. Smooth muscle is found in the walls of internal organs and blood vessels, not in the heart. Skeletal muscle is attached to bones and helps in movement but is not found in the heart. Striated muscle is a broader term that includes both cardiac and skeletal muscle, but specifically, cardiac muscle refers to the muscle tissue of the heart.

5. When are gallstones most problematic?

• A. When they block a duct
• B. When they contain cholesterol
• C. When they contain bilirubin
• D. When they begin to dissolve

Correct answer: A

Rationale: Gallstones become most problematic when they block a duct, such as the bile duct or cystic duct. This blockage can lead to various complications, including inflammation, infection, and even damage to the gallbladder or liver. In severe cases, a blocked duct can cause intense pain, jaundice, and other serious symptoms that require medical intervention. Choices B, C, and D are incorrect because the presence of cholesterol or bilirubin in gallstones or the process of dissolution do not necessarily indicate when gallstones become most problematic. The critical issue arises when the stones obstruct a duct, leading to complications.

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