Which of the following is a hormone pair that acts as antagonists in the body?
insulin and glucagon
Ghrelin and gastrin
Calcitonin and melatonin
Androsterone and estradiol
The Correct Answer is A
a. Insulin and glucagon: These hormones have opposite effects on blood glucose levels; insulin decreases blood glucose by facilitating cellular uptake, while glucagon increases blood glucose by stimulating glycogen breakdown and gluconeogenesis.
b. Ghrelin and gastrin: Ghrelin stimulates appetite, and gastrin stimulates gastric acid secretion, but they do not directly oppose each other.
c. Calcitonin and melatonin: Calcitonin lowers blood calcium levels, while melatonin regulates sleep-wake cycles; they do not act as antagonists.
d. Androsterone and estradiol: These are sex hormones with different roles but are not direct antagonists; they do not have opposing effects in the body.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
a: Chest cavity compresses the lungs - This is incorrect; during inspiration, the chest cavity expands, not compresses.
b: Length of the thoracic cavity decreases - This is incorrect; during inspiration, the thoracic cavity increases in length as it expands.
c. Diameter of the thoracic cavity increases. When inspiratory muscles contract, such as the diaphragm and external intercostal muscles, the thoracic cavity expands, increasing its volume. This expansion decreases the pressure within the lungs, causing air to flow in (inspiration).
d: Diaphragm rises up in the abdomen - This is incorrect; during inspiration, the diaphragm contracts and moves downward, not upward.
Correct Answer is A
Explanation
a. QRS wave: The ECG (electrocardiogram) measures the electrical activity of the heart. The QRS complex represents ventricular depolarization, the spread of electrical excitation through the ventricles causing them to contract.
b. P wave: The P wave represents atrial depolarization, the electrical impulse moving through the atria.
c. T wave: The T wave represents ventricular repolarization, the ventricles relaxing after contraction.
d. U wave: The U wave is a small wave of uncertain origin, not related to ventricular depolarization.
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