9.6

• Nicotine is absorbed in the lungs and travels to the brain via the bloodstream.
• Nicotine has a similar shape to acetylcholine, which binds to cholinergic receptors.
• Nicotine has a stimulant effect that causes symptoms of sharpness and relaxation.
• Lidocaine is absorbed through the skin or injected.
• Lidocaine blocks voltage-gated Na+ ion channels, preventing the postsynaptic neuron from depolarising.
• Lidocaine prevents the transmission of pain signals, acting as an anaesthetic.
• Cobra venom blocks acetylcholine receptors on the diaphragm, preventing the muscle from contracting during inhalation.
• Cobra venom disrupts normal breathing.