Drugs

Medicines

• Paracetamol
• Penecillin
• Insulin

Everyday substances

• Caffeine
• Nicotine
• Alcohol

Illegal substances

• Cannabis
• Heroin
• Cocaine

Drug - any chamical that affects the way your body functions.

Legal drugs - carry risks of dependancy and damage > misused.

Parkinson's disease - progressive loss of neurones in part of the brain (produces chemical dopamine).

Symptoms - tremors, stiffness, slow movements etc.

Enzyme in synapse breaks down dopamine, continues > not enough to balance ACh > overall effect - extensive loss of dopamine in brain.

Drug treatments - increase dopamine in brain or oppose action of ACh.

Dopamine replacement drugs > levodope and a chamical > break down in body to form dopamine > chamical ensure right amount.

Drugs that mimic action of dopamine > taken alone before levodopa > reduce long-term side effects.

Drugs stop breakdown of dopamine > used with levodopa > given when dopamine replacement drugs start to lose effectiveness.

Anticholinergic drugs > Blocks action of ACh.

Diamorphine (heroin) > relieve severe pain > chamical derative of morphine > more solube > penetrates brain more rapidly.

Diamorphine hydrochloride > group opioids > mimic effects naturally occurring pain-reducing chemicals - endorphins > combine with opioid receptors in brain > block transmission of pain signals > less pain felt.

Opioids attach to specific membrane protein - opioid receptor > located on sensory neurone cell mebranes > large concentrations in brain and spinal cord > chain or reactions stimulated > depression of normal activity of neurone for short time > leave receptor > normal neurone function.

Cannabis > derived from plant > central nervous system depressant > dried leaves (marijuana) > solin resin (hash) > thick liquid from flowers (hash oil).

Uses > therapeutic > relieve symptoms of multiple sclerosis et al > medication for terminally ill > illegal since 1928.

Uses > recreational use > effects > talkativeness, cheerfulness, relaxation etc > helps relax > time and space altered.

Physical dependance > repeated heavy use of drug > change body chemistry > suffer withdrawal symptoms.

Psychological dependance > become more important than other activities > crave drug > find difficult stopping or cutting down.