- Nicotine and carbon monoxide in cigarettes affect the ability of the cardiovascular system to function properly
- Nicotine is the addictive component of cigarettes. It causes vasoconstriction, which is the narrowing of blood vessels
- Vasoconstriction limits the flow of blood around the body, increases blood pressure and makes it harder for oxygen to reach all body cells
- This lack of oxygen can force cells to respire anaerobically, creating lactic acid
- Nicotine can also make platelets ‘sticky’ and they clump together, potentially forming a thrombosis (blood clot)
- Once inhaled, carbon monoxide in cigarettes binds to haemoglobin instead of oxygen
- This is because chemically carbon monoxide has a much higher affinity for haemoglobin than oxygen
- When this happens, oxygen cannot bind to haemoglobin and carboxyhaemoglobin (COHb) is formed instead of oxyhaemoglobin
- This decreases the amount of oxygen delivered to cells for aerobic respiration and cells may have to respire anaerobically instead
- This forces the heart to work harder to pump and deliver adequate oxygen, increasing heart rate and causing breathlessness
- Carbon monoxide also promotes the release of free radicals, such as peroxides and superoxides
- Carbon monoxide can also cause platelets and neutrophils to stick together, affecting the ability of white blood cells to fight infection
The drug nicotine has a similar structure to acetylcholine. Suggest the effects on brain neurons of inhaling nicotine from a cigarette.
Nicotine will fit into membrane receptors and is not broken down by enzymes. This means that action potentials are generated for a long period of time.