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Cannabis smoking is the inhalation of smoke or vapors released by heating the flowers, leaves, or extracts of cannabis and releasing the main psychoactive chemical, Δ9-tetrahydrocannabinol (THC), which is absorbed into the bloodstream via the lungs.
Apart from being smoked and vaporized, cannabis (and its active cannabinoids) may be ingested, placed under the tongue or applied to the skin. The bioavailability characteristics and effects of smoking and vaporizing cannabis differ from other consumption methods in having a more rapid and predictable onset of effect.
"Drug Containing" cannabis (aka marijuana) can be smoked in a variety of pipe-like implements made in different shapes and of different materials ("bowls"), water pipes ("bongs"), cigarettes ("joints"), or blunts. When smoking a joint or blunt with someone else or a group of people, it is common courtesy to take two inhalations ("pulls", "hits", "rips") then pass it on. With a pipe, bowl, bong, or vape, one good hit is the norm.
Joint is a slang term for a cigarette filled with cannabis, instead of tobacco. Alternatively, mainly in Europe, joints may contain tobacco (commonly dubbed "a spliff" in Jamaica) or various non-addictive herbs. Sometimes a joint will contain Kief or hashish; hashish can be heated and made to crumble before placement within the joint. Specially manufactured rolling papers are most often used in industrialized countries; however, recycled brown paper and newspaper are commonly used in the developing world. Modern papers are now made from a wide variety of materials including rice, hemp, and flax. A joint typically contains 250–750 mg net weight of cannabis and/or fillers.
Pipe or bowl
Pipes made for smoking cannabis, sometimes called pieces or bowls, are made of a variety of materials, including metal fittings, ceramic, Borosilicate glass, stone, wood, bamboo among other materials. Subtypes include one-hitters, bubblers, chillums, glass blunts, corn cob pipes, and standard hand pipes. Pipes vary greatly in shape and materials, and most are handmade. The common thread between them is having a narrow screened receptacle ("bowl"), a "stem" (which may be a long flexible tube as on hookahs and vaporizers), and a "mouthpiece". The smoking material is placed in the receptacle and affected with a heat source while air is drawn through the bowl and stem to the user.
The exterior surface of the bowl of some pipes may be fashioned with some kind of design. The character Henry Flower, in James Joyce's Ulysses carries a tobacco pipe with the bowl carved into a head: "He carries a silverstringed inlaid dulcimer and a longstemmed bamboo Jacob’s pipe, its clay bowl fashioned as a female head."
Thomas Curtis' London Encyclopaedia of 1839 describes a "fumigator", an instrument found in a doctor's surgery "for injecting tobacco smoke into the anus of drowned persons, with a view to excite the irritability of the muscles". Curtis describes the best as being made by a W. Willurgby "the bowl of which is of cast brass and is large enough to contain about an ounce and a half of tobacco".
A bubbler is a mix of a bong and a pipe, and another way to smoke cannabis. A bubbler contains a chamber for water, commonly with a down stem directly connected to the bowl of the piece. A bubbler normally has a dedicated carb, which may not be included on a bong.
A bong is similar to a pipe, only it has a water-chamber through which cannabis smoke passes prior to inhalation and a wide "mouth" typically around 3.8–5.1 cm (1.5–2.0 in) in diameter. Users fill the bong with water, sometimes also adding ice in order to cool the smoke. This cooling effect allows a larger amount of cannabis to be consumed at once while reducing the discomfort caused by the heat of the smoke. The bowl and stem assembly of most bongs is removed briefly after the cannabis is burned, allowing clean air to circulate and clear the smoke chamber, ensuring no smoke dissipates without being properly consumed.
A gravity bong (also known as a grav, bucket, submarine, geeb, or GB) is a hydropneumatic device used for smoking cannabis. One variant consists of a bucket of water in which is typically placed a bottle with the bottom cut off, such as a 2-litre PET soft drink bottle. Some kind of cap or screen is rigged over the mouth of the bottle and filled with hash or cannabis. A flame is then held near enough to heat the drug while the bottle is slowly raised out of the water, creating a negative gauge pressure inside the bottle, drawing smoke from the heated cannabis—along with air—into the vacuum. The cap or screen is removed once the bottle is almost full, the user's mouth is placed over the mouth of the bottle and the bottle pushed back down into the water, causing the pressure to rise and forcing the smoke into the lungs. There are many variants on this basic premise, such as using a large water cooler tank in lieu of a soft drink bottle.
Waterfall (gravity) bong
Similar to a gravity bong, a waterfall bong utilizes both a bottle and a cap or screen rigged over the bottle's mouth to hold cannabis. In this case, however, the bottle—which has one or several holes drilled near or at the bottom—is either filled with water or placed in a larger container filled with water before the cannabis is packed. The holes are then uncovered, or the bottle is simply raised from the container, evacuating the water either onto the ground or back into the container. When heat is applied to the drug, the resultant smoke is forced into the bottle with negative gauge pressure, as with the gravity bong. Once the water is evacuated, the smoke can be inhaled from the bottle. Variations on this concept are also used.
Vaporizers (vape pens and/or stationary platform) are devices used to extract the active ingredients of cannabis, tobacco (E-cigarettes) or any plant material at lower than burning temperature, eliminating carbon monoxide and carcinogenic "tars" found hazardous in smoke. 197C/385F is frequently mentioned as a good vaporizing temperature for favored cannabinoids. According to the journal Clinical Pharmacology & Therapeutics, vaporizing cannabis is a safe and more effective way (than smoking) of delivering THC to patients for medical uses. The feasibility of vaporization of THC has been demonstrated in a series of laboratory studies involving different vaporizer designs. An electric vaporizer was shown to release substantial amounts of the THC while producing no measurable amounts of the benzene, toluene, and naphthalene, which are generated when marijuana is smoked.
This method involves multiple persons smoking cannabis in an enclosed space such as a car with no way for smoke to escape. In addition to the primary smoke from the chosen smoking device(s), secondhand smoke is repeatedly inhaled and exhaled.
Health effects of smoking
A 2013 literature review said that exposure to cannabis had biologically-based physical, mental, behavioral and social health consequences and was "associated with diseases of the liver (particularly with co-existing hepatitis C), lungs, heart, and vasculature". The authors cautioned that "evidence is needed, and further research should be considered, to prove causal associations of marijuana with many physical health conditions".
There is conflicting data on the correlation of an increase in the incidence of lung cancer and cannabis smoking. A systematic review evaluating 19 studies from 1966 to 2006 found no significant tobacco-adjusted association between cannabis smoking and lung cancer development despite evidence of precancerous histopathologic changes of the respiratory mucosa. Some studies indicate increased rates of cancer and others do not. The studies do indicate increased prevalence of pre-cancerous changes in the user's airways.
A 2012 literature survey by the British Lung Foundation identified cannabis smoke as a carcinogen and also found awareness of the danger was low compared with 40% of under 35s thinking that cannabis was not harmful. Other observations include increased risk from each cigarette due to drawing in larger puffs of smoke than cigarette smokers and holding the smoke in for longer; lack of research on the effect of cannabis smoke alone due to common mixing of cannabis and tobacco and frequent cigarette smoking by cannabis users; low rate of addiction compared to tobacco; and episodic nature of cannabis use compared to steady frequent smoking of tobacco.
A 2014 research in Spain reveals that because Alzheimer’s disease involves a wide range of complicated mechanisms and until now, its origin has yet to be discovered; any treatments effective against it should be on a multi-target basis. And this is why cannabis, with the cannabinoid compounds possessing various medical properties, should be taken into account.
Smoking cannabis has been demonstrated to cause chronic bronchitis, airflow obstruction, impaired large airway function and hyperinflation. There is a dose-response relationship to marijuana's effect on the lungs, with one marijuana joint equivalent to 2.5-5 cigarettes, possibly due to different inhalation techniques and lack of filters.
Macroscopic emphysema is rarely seen although large apical bullae in a paraseptal distribution have been described with secondary spontaneous pneumothorax as a complication.
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