Nokea
Which of the following structures is responsible for transmitting electrical impulses in the nervous system?
- A. Neuron
- B. Axon
- C. Myelin
- D. Dendrite
Correct Answer: A
Rationale: The correct answer is A: Neuron. Neurons are specialized cells that transmit electrical impulses in the nervous system. While the axon is the part responsible for conducting these impulses over long distances, it is the neuron as a whole that is ultimately responsible for transmitting electrical impulses. Myelin is a fatty substance that surrounds and insulates axons, speeding up signal transmission. Dendrites, on the other hand, receive signals from other neurons. Therefore, although the axon plays a significant role in transmission, the neuron is the fundamental unit responsible for transmitting electrical impulses in the nervous system.
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What is the role of the pancreas in the digestive system?
- A. To store bile
- B. To secrete digestive enzymes
- C. To digest proteins
- D. To absorb nutrients
Correct Answer: B
Rationale: The correct answer is B: 'To secrete digestive enzymes.' The pancreas plays a crucial role in the digestive system by secreting digestive enzymes that aid in breaking down food in the small intestine. These enzymes help in the digestion of carbohydrates, fats, and proteins, facilitating the absorption of nutrients from the digested food. Choice A is incorrect because the pancreas is not responsible for storing bile; the gallbladder stores bile. Choice C is incorrect because the pancreas secretes enzymes for protein digestion but does not digest proteins itself. Choice D is incorrect as the absorption of nutrients primarily occurs in the small intestine, not in the pancreas.
Which of the following vessels is responsible for transporting blood from the heart to the lungs?
- A. Pulmonary vein
- B. Pulmonary artery
- C. Aorta
- D. Superior vena cava
Correct Answer: B
Rationale: The correct answer is B, Pulmonary artery. The pulmonary artery carries deoxygenated blood from the heart's right ventricle to the lungs for oxygenation. This blood then undergoes the gas exchange process in the lungs, where carbon dioxide is removed, and oxygen is absorbed. The pulmonary vein, identified in choice A, carries oxygenated blood from the lungs back to the heart, which is the opposite direction of the blood flow specified in the question. Choice C, Aorta, is responsible for carrying oxygen-rich blood from the heart's left ventricle to the rest of the body, not to the lungs. Choice D, Superior vena cava, returns deoxygenated blood from the upper body to the heart's right atrium, but it does not transport blood specifically to the lungs as requested in the question.
Which of the following is the smallest unit of matter?
- A. Molecule
- B. Atom
- C. Compound
- D. Element
Correct Answer: B
Rationale: An atom is the fundamental building block of matter, while molecules are formed by the combination of atoms.
Which of the following best describes the function of the pericardium?
- A. Regulating blood flow through valves within the heart.
- B. Acting as a protective sac surrounding the heart.
- C. Generating the electrical impulses for heart contractions.
- D. Transmitting electrical signals between the atria and ventricles.
Correct Answer: B
Rationale: The pericardium is a double-layered sac that surrounds and protects the heart. Its main functions include preventing overfilling of the heart, providing a physical barrier against infection and inflammation, and reducing friction between the heart and surrounding structures. Choices A, C, and D do not accurately describe the function of the pericardium. Option B is the correct answer as it aligns with the protective and supportive role of the pericardium, distinguishing it from the functions attributed to choices A, C, and D.
Which of the following is an example of a fibrous protein?
- A. Insulin
- B. Keratin
- C. Hemoglobin
- D. Collagen
Correct Answer: D
Rationale: A) Insulin is a hormone, not a fibrous protein. It is produced in the pancreas and regulates blood sugar levels.
B) Keratin is a fibrous structural protein found in hair, nails, and the outer skin layer, providing strength and protection.
C) Hemoglobin is a globular protein in red blood cells responsible for oxygen transport; it is not fibrous.
D) Collagen is a fibrous protein found in tendons, ligaments, and skin, offering strength and structure to connective tissues. Therefore, the correct answer is collagen, making it the main component of various connective tissues.