Question

The data below shows the concentration of nicotine smoked by a smoker taking 10 puffs/minute.

Graph: "Smoking Cigarette" - concentration of nicotine in blood (mg/cm³) plotted against time (minutes).

How does cigarette smoking result in high blood pressure and increase in heart rate ?

Hint:

Nicotine releases adrenaline and noradrenaline from the adrenal medulla, which speed up the heart and narrow blood vessels.

Answer 1

Step 1: Identify the active substance:
Nicotine in cigarette smoke acts on the adrenal gland, which sits above the kidney.

Step 2: Hormone release:
Nicotine stimulates the adrenal medulla to release adrenaline and noradrenaline into the blood.

Step 3: Effect on the heart:
Adrenaline and noradrenaline act on the heart. They make it beat faster and with more force. So the heart rate increases.

Step 4: Effect on blood vessels:
These hormones also make the small arteries narrow (vasoconstriction). The blood meets more resistance while flowing.
Higher output and higher resistance together raise the blood pressure.

Step 5: Extra support from carbon monoxide:
Carbon monoxide in smoke reduces oxygen carried by haemoglobin. The heart pumps harder to deliver enough oxygen, which adds to the strain.

Final Answer:
Nicotine makes the adrenal gland release adrenaline and noradrenaline, which raise the heart rate and narrow the blood vessels, so blood pressure goes up.