MARIJUANA
| Facts on how drugs hurt you. |
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Did you know marijuana can cause come people to lose focus on events around them? It makes others more aware of their physical sensations, and it has still more effects on other people.
All of these different changes are caused by chemicals that affect the brain. More than 400 chemicals are in the average marijuana plant. When smoked, heat produces even more of them!
When someone uses marijuana, these chemicals travel through the bloodstream and quickly attach to special places on the brain's nerve cells. These places are called receptors, because they receive information from other nerve cells and from chemicals. When a receptor receives information, it causes changes in the nerve cell.
The chemical in marijuana that has a big impact on the brain is called THC -- tetrahydrocannabinol. (Whew! Try saying that 10 times fast.) Scientists recently discovered that some areas in the brain have a lot of THC receptors, while other have very few or none. One region of the brain that contains a lot of THC receptors is the hippocampus, which processes memory. When THC attaches to receptors in the hippocampus, it weakens short-term memory.
The hippocampus also communicates with other brain regions that process new information into long-term memory. (That's how you can remember today's math lesson or a new friend's phone number.) In the brain, under the influence of marijuana, new information may never register -- and may be lost from memory.
