Alcohol is rapidly absorbed into the CNS via the lipid bilayer. The effects can be felt in a few minutes. More alcohol means that the gradient outside the cell is much higher and moves more quickly into the cell. The lipid bilay doesn't inhibit the movement at all.
Alcohol acts as a general central nervous system depressant, but it also affects specific areas of the brain to a more extent degree than others. Memory impairment due to alcohol has been linked to disruption of hippocampal function -- in particular affecting gamma-Aminobutyric acid (GABA) and N-methyl-D-aspartate (NMDA) neurotransmission which negatively impacts long-term potentiation (LTP). The molecular basis of LTP is associated with learning and memory. Particularly, damage to hippocampal CA1 cells adversely affects memory formation, and this disruption has been linked to dose-dependent levels of alcohol consumption. At higher doses, alcohol significantly inhibits neuronal activity in the CA1 and CA3 pyramidal cell layers of the hippocampus.This impairs memory encoding since the hippocampus plays an important role in the formation of new memories.
Alcohol also impairs and alters functioning in the cerebellum, which affects motor function and coordination. It has a notable inhibitory effect on neurons of the cerebral cortex, affecting and altering thought processes, decreasing inhibition, and increasing the pain threshold. It also decreases sexual performance by depressing nerve centers in the hypothalamus. Alcohol also has an effect on urine excretion via inhibition of anti-diuretic hormone (ADH) secretion of the pituitary gland. Lastly, it depresses breathing and heart rate by inhibiting neuronal functioning of the medulla.