Statement I: Smoking increases carbon monoxide (CO) content in blood and increases the concentration of haem-bound oxygen.
Statement II: Nicotine stimulates adrenal gland to release adrenaline and nor-adrenaline into blood circulation, both of which raise blood pressure and increase heart rate.
In the light of the above statements, choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Only Statement II is correct.
Tobacco is smoked, chewed or used as snuff. Its smoke changes the blood in two ways that the book describes: carbon monoxide from the smoke enters the blood, and nicotine acts on the adrenal gland.
Statement I: Smoking increases carbon monoxide (CO) content in blood and increases the concentration of haem-bound oxygen. — False. Smoking does raise the CO content of the blood, but it reduces the haem-bound oxygen. CO takes the place of oxygen on haemoglobin, so less oxygen is carried and the body suffers from oxygen deficiency.
Statement II: Nicotine stimulates adrenal gland to release adrenaline and nor-adrenaline into blood circulation, both of which raise blood pressure and increase heart rate. — True. Nicotine is an alkaloid present in tobacco. The adrenaline and nor-adrenaline it releases raise blood pressure and increase heart rate.
NCERT Extract:
Drugs and Alcohol Abuse – “… Tobacco contains a large number of chemical substances including nicotine, an alkaloid. Nicotine stimulates adrenal gland to release adrenaline and nor-adrenaline into blood circulation, both of which raise blood pressure and increase heart rate. Smoking is associated with increased incidence of cancers of lung, urinary bladder and throat, bronchitis, emphysema, coronary heart disease, gastric ulcer, etc. Tobacco chewing is associated with increased risk of cancer of the oral cavity. Smoking increases carbon monoxide (CO) content in blood and reduces the concentration of haembound oxygen. This causes oxygen deficiency in the body.”