Types of drugs and examples
Drugs and Parkinson's disease
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.
Drug and what it does
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.