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intoxicationDrunkenness, in its most common usage, is the state of being intoxicated with alcohol (i.e. ethanol) to a sufficient degree to impair mental and motor functioning.
1 Effects of alcohol on the body
Alcohol is a potent drug and consequently it has a range of side effects, some pleasurable and some less so. The amount consumed and the circumstances under which the alcohol was taken can play a large part in determining the extent of drunkenness. Drinking after eating a large meal is much less likely to induce drunkenness compared to drinking on an empty stomach. This is because the presence of food in the stomach is able to slow the absorption of alcohol in to the bloodstream, diluting its effects over a longer period of time.
Cell membranes are highly permeable to alcohol, so once alcohol is in the bloodstream it can diffuse into nearly every tissue of the body. This can contribute to the correspondingly dramatic effect seen when large amounts are taken.
Alcohol has a biphasic relationship on the body - its effects transform over an evening of drinking, from initial feelings of relaxation and cheerfulness to blurred vision and problems with coordination. After excessive drinking unconsciousness can occur, and in extreme cases (when the concentration of alcohol in the bloodstream is over about 500mg per 100ml) alcohol can even cause death. Death can also be caused by vomiting blocking the trachea and causing choking. An appropriate first aid response to an unconscious, drunken person is a manouever known as the recovery position.
1.1 Moderate doses
Although alcohol is commonly thought of purely as a depressant, at low concentrations it can actually stimulate certain areas of the brain. Alcohol sensitises the N-methyl-D-aspartate ( NMDANMDA FormulaCHNO Molecular mass147. 13 D NMDA (N-methyl-D-aspartatic acid) is an amino acid derivative acting as specific agonist at the NMDA receptor, and therefore mimics the action of the neurotransmitter glutamate on that receptor. In contrast to glut) system of the brain, making it more receptive to the neurotransmitterA neurotransmitter is a type of molecule that carries signals between neurons (nerve cells) at synapses in the nervous system. Neurotransmitters may be either excitatory ( EPSPs) or inhibitory ( IPSPs). That is, they may foster the initiation of a nerve i glutamate. Stimulated areas include the cortexThe outermost layer of the brain, the cortex is rich in neurons and is the site of most sophisticated neural processing (See also: cerebral cortex). Or, more generally, the outermost portion of certain biological structures (See below). The human cortex i, hippocampusThe hippocampus is a part of the brain located inside the temporal lobe (humans have two hippocampi, one in each side of the brain). It forms a part of the limbic system and plays a part in memory and navigation. The name derives from its curved shape, wh and nucleus accumbensThe nucleus accumbens is a collection of neurons in the basal forebrain region of reptiles and higher organisms which play an important role in reward, pleasure and addiction. It is part of the ventral continuation of the dorsal striatum and shares genera, which are responsible for thinking and pleasure seeking. Another one of alcohol's agreeable effects is body relaxation, possibly caused by heightened alpha brain waves surging across the brain. Alpha waves are observed (with the aid of EEGs) when the body is relaxed. Heightened pulses are thought to correspond to higher levels of enjoyment.
A well-known side effect of alcohol is the loosening it has on inhibition s. Areas of the brain responsible for planning and motor learning are dulled. A related effect, caused by even low levels of alcohol, is the tendency for people to become more animated in speech and movement. This is due to increased metabolism in areas of the brain associated with movement, such as the nigrostriatal pathway. This causes reward systems in the brain to become more active, and combined with released inhibition can induce people to behave in an uncharacteristically loud and cheerful manner.
Behavioural changes associated with drunkenness are, to some degree, contextual. A scientific study found that people drinking in a social setting significantly and dramatically altered their behaviour immediately after the first sip of alcohol, well before the chemical itself could have filtered through to the nervous system. Likewise, people consuming non-alcoholic beer or "shirley temple" mixed drinks have been observed exhibiting increasingly drunk-like behavior on a par with their alcohol drinking companions even though their own drinks contained no alcohol whatsoever.
