They are important for lung function, since their purpose is the exchange of oxygen and carbon dioxide. When the airways are blocked by a mucous plug, foreign object, or tumor, the alveoli are unable to fill with air and collapse of lung tissue can occur in the affected area.
Testing Positive for Marijuana Does Not Indicate Impairment Someone can test positive for marijuana days or even weeks after they last used it. by Dr. Carl Hart @drcarlhart. AAs Oregonians consider their vote on tax and regulation of marijuana, it is important for them to have access to sound information grounded in science.
Quick Answer. The results from a urine test can take from a few days to a week for a positive screen, while negative results are usually found in a single day. Additionally, if a rapid test is requested, the results are received on the same day. Some drugs are detectable in urine from a couple days to three or four weeks with chronic use, such as marijuana. To reduce the chances of a false-positive, provide an up-to-date history of all prescription, over-the-counter and herbal drug use prior to taking the urine test.