Marijuana is a common name for the hemp plant, cannabis sativa. However, marijuana, also known as pot, grass or weed, does not contain just one chemical. In fact, it contains 61 known relatives of the primary active ingredient, Delta-9-Tetrahydrocannabinol (THC), and more than 400 known chemical toxins also have been found in marijuana. When burned, even more toxic compounds are produced. Smoking marijuana can cause faster heartbeat and pulse rate, bloodshot eyes, dry mouth and dry throat, reduce, short term memory, alter sense of time, reduces concentration and coordination. The typical reaction to the drug is known as an Acute Anxiety Panic Reaction which is an extreme fear of losing control. However the symptoms usually disappear in a few hours. Depending on the amount of THC, Marijuana use can increase the heart rate as much as 50 percent. It can cause chest pain in people who have a poor blood supply to the heart. Long-term regular users of marijuana may become psychologically dependent. They may have a hard time limiting their use and may need more of the drug to get high. Also, they may develop problems with their jobs and personal relationships and the drug can become the most important aspect of their lives. Compared to cigarette smokers, marijuana users often inhale the unfiltered smoke deeply and hold it in their lungs as long as possible. As a result, the smoke is in contact with lung tissues for long periods of time, which irritates the lungs and damages the way they work. Marijuana smoke contains some of the same ingredients in tobacco smoke that can cause emphysema and cancer. Inspection of human lung tissue that had been exposed to marijuana smoke over a long period of time in a laboratory showed cellular changes called metaplasia, that are considered to be precancerous. In laboratory test, the tars from marijuana smoke have produced tumors when applied to animal skin. No one knows exactly how the brain functions by itself, let alone full of marijuana. But we do know that it tilts the balance of chemicals that regulate mood, energy, appetite and attention and reduces logical thinking and calculating skills. Once inhaled, the THC reaches your brain within seconds. The cannabinoid receptors are activated by a neurotransmitter called anandamide. THC and anandamide are cannabinoid chemicals. The THC binds with cannabinoid receptors and activates neurons, which causes unpleasant effects on the mind and body. High concentrations of cannabinoid receptors are in the hippocampus, cerebellum and basal ganglia. The hippocampus is located within the temporal lobe and is important for short-term memory. When the THC binds with the cannabinoid receptors inside the hippocampus, it interferes with the memory of recent events. THC also affects coordination, which is controlled by the cerebellum. The basal ganglia controls unconscious muscle movements, which is why motor coordination is impaired when under the influence of marijuana. Accounts of increased food intake have always been reported by marijuana smokers; the so-called munchies. Overall, studies show that people using marijuana eat more but the food they eat is generally snack food, like cookies and junk food. They also exercise less and sleep more, all of which contributes to weight gain.

Works Cited
1. Bonsor, Kevin. "How Marijuana Works." How Stuff Works. 2006. How Stuff Works, Inc.. 26 Sep 2006 <http://science.howstuffworks.com/marijuana.htm>.
2. "Cannabis (drug)." Wikipedia, The Free Encyclopedia. 26 Sep 2006, 14:52 UTC. Wikimedia Foundation, Inc. 26 Sep 2006 <http://en.wikipedia.org/w/index. php?title=Cannabis_%28drug%29&oldid=77912764>.
3. "Marijuana Abuse." NIDA. 1 July 2005. National Institute of Health. 26 Sep 2006 <http://www.nida.nih.gov/ResearchReports/Marijuana/Marijuana3.html>.
4. "How Marijuana Smoking Affects The Body." Schick Shadel Hospital. 2004. Schick Shadel Hospital. 26 Sep 2006 <http://schick-shadel.com/marijuana.asp>.