Nokea
Which hormone, produced by the thyroid gland, regulates calcium levels in the blood by enhancing calcium absorption in the intestines and reducing calcium loss in the kidneys?
- A. Calcitonin
- B. Parathyroid hormone (PTH)
- C. Thyroxine
- D. Insulin
Correct Answer: A
Rationale: Calcitonin is the hormone produced by the thyroid gland that regulates calcium levels in the blood. It enhances calcium absorption in the intestines and reduces calcium loss in the kidneys. Parathyroid hormone (PTH) operates oppositely to calcitonin by increasing calcium levels in the blood. Thyroxine is a thyroid gland hormone that primarily regulates metabolism, not calcium levels. Insulin, produced by the pancreas, is responsible for controlling blood sugar levels, not calcium levels. Therefore, the correct answer is Calcitonin as it specifically targets calcium regulation in the body.
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Calcitonin, a hormone that helps regulate calcium levels, is produced by the:
- A. Thyroid gland
- B. Parathyroid gland
- C. Thymus gland
- D. Adrenal gland
Correct Answer: A
Rationale: Calcitonin is a hormone produced by the thyroid gland. It helps regulate calcium levels in the body by inhibiting the breakdown of bone and promoting calcium excretion by the kidneys. The parathyroid gland produces parathyroid hormone (PTH), which works in opposition to calcitonin to regulate calcium levels. The thymus gland is involved in the development of the immune system, and the adrenal gland produces hormones such as cortisol and adrenaline. Therefore, the correct answer is the thyroid gland as it specifically secretes calcitonin for calcium regulation.
What term describes the maximum displacement of particles from their rest position in a wave?
- A. Frequency
- B. Wavelength
- C. Amplitude
- D. Velocity
Correct Answer: C
Rationale: The term that describes the maximum displacement of particles from their rest position in a wave is called the amplitude. Amplitude is a measure of the strength or intensity of a wave and is represented by the height of the wave from the rest position to the crest (or trough) of the wave. Frequency (A) refers to the number of complete wavelengths that pass a point in a given time. Wavelength (B) is the distance between two consecutive crests (or troughs) of a wave. Velocity (D) is the speed of the wave, not the maximum displacement of particles from their rest position.
What is the general formula for an alcohol?
- A. Câ‚™Hâ‚‚â‚™
- B. CₙH₂ₙ₊₂
- C. Câ‚™H₂ₙ₋â‚
- D. Câ‚™Hâ‚‚â‚™O
Correct Answer: D
Rationale: The correct general formula for an alcohol is CnH2n+1OH, which can be simplified to CnH2nO. In this formula, 'n' represents the number of carbon atoms, '2n' represents the number of hydrogen atoms, and 'O' represents the oxygen atom present in the hydroxyl group of the alcohol. Therefore, the correct general formula for an alcohol is CnH2nO. Choice A, Câ‚™Hâ‚‚â‚™, does not account for the oxygen atom, which is essential in alcohols. Choice B, Câ‚™H₂ₙ₊₂, does not include the oxygen atom or the necessary hydrogen atoms for the hydroxyl group. Choice C, Câ‚™H₂ₙ₋â‚, lacks the oxygen atom and also does not fulfill the requirements of the hydroxyl group. Thus, the most accurate representation of the general formula for an alcohol is CnH2nO.
What is the primary function of the liver?
- A. To produce bile, which aids in the digestion of fats
- B. To store energy in the form of glycogen
- C. To produce proteins that assist in blood clotting
- D. To detoxify harmful substances in the body
Correct Answer: D
Rationale: The primary function of the liver is to detoxify harmful substances in the body. While the liver does produce bile to aid in the digestion of fats, this is not its primary function. Bile is stored in the gallbladder and released into the small intestine for fat digestion. Storing energy in the form of glycogen is a function of the liver, but not its primary one. Glycogen serves as a reserve of glucose. Although the liver produces proteins that assist in blood clotting, such as fibrinogen and prothrombin, this is not its main function. These proteins play a crucial role in blood clotting to prevent excessive bleeding. Therefore, the primary role of the liver is to detoxify harmful substances by processing and removing toxins, drugs, alcohol, and other harmful substances from the bloodstream, thereby reducing their harmful effects.
What is the primary function of the atrioventricular (AV) node within the heart?
- A. Generate the electrical impulse for contraction (pacemaker function)
- B. Transmit the electrical impulse from the atria to the ventricles, regulating the timing of contraction.
- C. Increase blood pressure within the ventricles during systole.
- D. Separate oxygenated and deoxygenated blood flow in the heart.
Correct Answer: B
Rationale: The correct answer is B: Transmit the electrical impulse from the atria to the ventricles, regulating the timing of contraction. The primary function of the atrioventricular (AV) node is to coordinate the transmission of electrical signals between the atria and the ventricles. It ensures proper timing between atrial and ventricular contractions, allowing for efficient blood pumping through the heart. Choice A is incorrect because the AV node does not generate the initial electrical impulse; that role is typically attributed to the sinoatrial (SA) node. Choice C is incorrect as the AV node does not directly influence blood pressure within the ventricles. Choice D is also incorrect as the separation of oxygenated and deoxygenated blood is primarily achieved by the anatomical structure of the heart (e.g., atria and ventricles) and not the AV node.