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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The gland located on top of the kidneys responsible for regulating blood pressure and electrolyte balance is the:
- A. Thyroid gland
- B. Pituitary gland
- C. Adrenal gland
- D. Parathyroid gland
Correct Answer: C
Rationale: The gland located on top of the kidneys responsible for regulating blood pressure and electrolyte balance is the adrenal gland. The adrenal gland produces hormones such as cortisol and aldosterone, which play a crucial role in regulating blood pressure and electrolyte balance in the body. The other choices, thyroid gland (choice A), pituitary gland (choice B), and parathyroid gland (choice D), do not have a primary role in regulating blood pressure and electrolyte balance. The thyroid gland is responsible for regulating metabolism, the pituitary gland controls various endocrine functions, and the parathyroid gland regulates calcium levels in the body.
From which type of tissue is the myelin sheath derived, a fatty substance that insulates nerve fibers?
- A. Epithelial tissue
- B. Muscle tissue
- C. Nervous tissue (glial cells)
- D. Connective tissue
Correct Answer: C
Rationale: The myelin sheath, a fatty substance that insulates nerve fibers, is derived from nervous tissue, specifically glial cells. Glial cells, including oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system, are responsible for producing the myelin sheath that surrounds and insulates nerve fibers, aiding in the conduction of nerve impulses. Epithelial tissue (Choice A), Muscle tissue (Choice B), and Connective tissue (Choice D) are not responsible for producing the myelin sheath; instead, nervous tissue (glial cells) plays this crucial role.
Which of the following pathologies is caused by a virus?
- A. Asthma
- B. Cystic Fibrosis
- C. Epiglottitis
- D. Influenza
Correct Answer: D
Rationale: The correct answer is D, Influenza. Influenza is a viral infection caused by the influenza virus. Asthma and cystic fibrosis are not caused by viruses. Asthma is a chronic respiratory condition related to inflammation and airway constriction, while cystic fibrosis is a genetic disorder affecting the lungs and other organs. Epiglottitis is most commonly caused by bacteria, particularly Haemophilus influenzae type B, rather than a virus.
In which group of the periodic table are alkali metals located?
- A. Group 1
- B. Group 2
- C. Group 7
- D. Group 8
Correct Answer: A
Rationale: Alkali metals, such as lithium, sodium, and potassium, are located in Group 1 of the periodic table. This group is known for its highly reactive properties, low melting points, and the tendency to form alkaline solutions when they react with water. Group 2 consists of alkaline earth metals and not alkali metals, making choice B incorrect. Group 7 includes halogens, while Group 8 includes noble gases. These groups do not contain alkali metals, so choices C and D are also incorrect. Therefore, the correct answer is Group 1.
Through which structure do the kidneys reabsorb water, salts, and nutrients and return them to the body?
- A. Renal artery
- B. Renal vein
- C. Nephron
- D. Glomerulus
Correct Answer: C
Rationale: The question has been corrected to specify the structure responsible for reabsorbing water, salts, and nutrients in the kidneys. The correct answer is the nephron, which is the functional unit of the kidney that performs filtration and reabsorption processes. The renal artery brings blood into the kidney for filtration, the renal vein carries filtered blood away from the kidney, and the glomerulus is a part of the nephron where filtration occurs. Therefore, the nephron is the structure that reabsorbs substances and returns them to the body.