O Levels Biology (5090)•5090/12/M/J/21

Explanation
Nicotine's Cardiovascular Effects in E-Cigarettes
Steps:
- Identify that e-cigarettes deliver nicotine without tobacco smoke's tar and chemicals.
- Recall nicotine stimulates the sympathetic nervous system, causing cardiovascular changes.
- Match options to nicotine-specific effects versus smoke-specific ones.
- Select the option describing heart rate, artery narrowing, and blood pressure increases.
Why A is correct:
- Nicotine activates adrenaline release, directly increasing heart rate, constricting arteries via vasoconstriction, and elevating blood pressure, as per physiological definitions of sympathomimetic effects.
Why the others are wrong:
- B: Airway inflation and mucus increase from irritants in smoke, not nicotine alone.
- C: Oxygen limitation from carbon monoxide in smoke, absent in e-cigarettes.
- D: Airway narrowing and coughing from smoke particulates and toxins, not isolated nicotine.
Final answer: A
Topic: Circulatory system
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