User:CaileanThompson/Forensic toxicology

Alcohol
Alcohol enters your central nervous system through the blood stream through the lining within your stomach and your small intestine. Once it is in your blood stream, is passes through your blood brain barrier via blood circulation. The alcohol absorbed will reduce your reflexes, interfere with nerve impulses, prolong muscle responses, and affect other parts of your body as well.

Marijuana
Marijuana, like alcohol, is also absorbed into the blood stream and passed through the blood brain barrier. However, the TCH that is released from marijuana attaches to the CB-1 cannabinoid receptors which causses all of the affects that you experience. This include, but not limited to, mood changes, altered perception of time, and increased sensitivity.

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Urine[edit]
A urine sample is urine that has come from the bladder and can be provided or taken post-mortem. Urine is less likely to be infected with viruses such as HIV or Hepatitis B than blood samples. Many drugs have a higher concentration and can remain for much longer in urine than blood. Collection of urine samples can be taken in a noninvasive way which does not require professionals for collection. Urine is used for qualitative analysis as it cannot give any indication of impairment due to the fact that drug presence in urine only indicates prior exposure. Different drugs can also stay in your urine for different amounts of time. For example, alcohol will stay within your urine for 7-12 hours, cocaine metabolites will stay for 2-4 days, and morphine will stay for 48-74 hours. One drug that will stay in your urine for a varying amount of time (dependent on the usage and frequency) is marijuana. For a single use, it will stay for 3 days, moderate use (4 times per week) will stay for 5-7 days, daily use of the drug will cause it to stay for 10=15 days, and a long-term heavy smoker will have it stay within their urine for less than 30 days

Hair sample[edit]
Hair is capable of recording medium to long-term or high dosage substance abuse. Chemicals in the bloodstream may be transferred to the growing hair and stored in the follicle, providing a rough timeline of drug intake events. Head hair grows at rate of approximately 1 to 1.5 cm a month, and so cross sections from different sections of the follicle can give estimates as to when a substance was ingested. Testing for drugs in hair is not standard throughout the population. The darker and coarser the hair the more drug that will be found in the hair. If two people consumed the same amount of drugs, the person with the darker and coarser hair will have more drug in their hair than the lighter haired person when tested. This raises issues of possible racial bias in substance tests with hair samples. Hair samples are analyzed using enzyme-linked immunosorbent assay (ELISA). In ELISA, an antigen must be immobilized to a solid surface and then complexed with an antibody that is linked to an enzyme.